Examinando por Autor "Sozzetti, A."

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Acceso Abierto
A precise architecture characterization of the π Mensae planetary system
(EDP Sciences, 2020-10-01) Damasso, D.; Sozzetti, A.; Lovis, C.; Barros, S. C. C.; Sousa, S. G.; Demangeon, O. D. S.; Faria, J. P.; Lillo Box, J.; Cristiani, S.; Pepe, Francesco; Rebolo, R.; Santos, Nuno C.; Zapatero Osorio, M. R.; González Hernández, J. I.; Amate, M.; Pasquini, L.; Zerbi, Filippo M.; Adibekyan, V.; Abreu, M.; Affolter, M.; Alibert, Y.; Aliverti, M.; Allart, R.; Allende Prieto, C.; Álvarez, D.; Alves, D.; Ávila, G.; Baldini, V.; Bandy, T.; Benz, W.; Bianco, A.; Borsa, F.; Bossini, D.; Bourrier, V.; Bouchy, F.; Broeg, C.; Cabral, A.; Calderone, G.; Cirami, R.; Coelho, J.; Conconi, P.; Coretti, I.; Cumani, C.; Cupani, G.; D´Odorico, V.; Deiries, S.; Dekker, H.; Delabre, B.; Di Marcantonio, P.; Dumusque, X.; Ehrenreich, D.; Figueira, P.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; Hughes, I.; Iwert, O.; Kerber, F.; Knudstrup, J.; Landoni, M.; Lavie, B.; Lizon, Jean Louis; Lo Curto, G.; Maire, C.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Micela, G.; Modigliani, A.; Molaro, P.; Monteiro, M. A.; Monteiro, M. J. P. F. G.; Moschetti, M.; Mueller, E.; Murphy, M. T.; Nunes, Nelson J.; Oggioni, L.; Oliveira, António; Oshagh, M.; Pallé, E.; Pariani, G.; Poretti, E.; Rasilla, J. L.; Rebordao, J.; Redaelli, E.; Riva, M.; Santa Tschudi, S.; Santin, P.; Santos, Pedro; Ségransan, D.; Schmidt, T. M.; Segovia, A.; Sosnowska, D.; Spanò, P.; Suárez Mascareño, A.; Tabernero, H. M.; Tenegi, F.; Udry, S.; Zanutta, A.; Swiss National Science Foundation (SNSF); Agenzia Spaziale Italiana (ASI); Fundação para a Ciência e a Tecnologia (FCT); Australian Research Council (ARC); Istituto Nazionale Astrofisica (INAF); 0000-0003-0987-1593; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The bright star pi Men was chosen as the first target for a radial velocity follow-up to test the performance of ESPRESSO, the new high-resolution spectrograph at the European Southern Observatory's Very Large Telescope. The star hosts a multi-planet system (a transiting 4 M-circle plus planet at similar to 0.07 au and a sub-stellar companion on a similar to 2100-day eccentric orbit), which is particularly suitable for a precise multi-technique characterization. Aims. With the new ESPRESSO observations, which cover a time span of 200 days, we aim to improve the precision and accuracy of the planet parameters and search for additional low-mass companions. We also take advantage of the new photometric transits of pi Men c observed by TESS over a time span that overlaps with that of the ESPRESSO follow-up campaign. Methods. We analysed the enlarged spectroscopic and photometric datasets and compared the results to those in the literature. We further characterized the system by means of absolute astrometry with HIPPARCOS and Gaia. We used the high-resolution spectra of ESPRESSO for an independent determination of the stellar fundamental parameters. Results. We present a precise characterization of the planetary system around pi Men. The ESPRESSO radial velocities alone (37 nightly binned data with typical uncertainty of 10 cm s(-1)) allow for a precise retrieval of the Doppler signal induced by pi Men c. The residuals show a root mean square of 1.2 m s(-1), which is half that of the HARPS data; based on the residuals, we put limits on the presence of additional low-mass planets (e.g. we can exclude companions with a minimum mass less than similar to 2 M-circle plus within the orbit of pi Men c). We improve the ephemeris of pi Men c using 18 additional TESS transits, and, in combination with the astrometric measurements, we determine the inclination of the orbital plane of pi Men b with high precision (i(b) =45.8(-1.1)(+1.4) deg). This leads to precise measurement of its absolute mass m(b) = =14.1(-0.4)(+0.5) M-Jup, indicating that pi Men b can be classified as a brown dwarf. Conclusions. The pi Men system represents a nice example of the extreme precision radial velocities that can be obtained with ESPRESSO for bright targets. Our determination of the 3D architecture of the pi Men planetary system and the high relative misalignment of the planetary orbital planes put constraints on and challenge the theories of the formation and dynamical evolution of planetary systems. The accurate measurement of the mass of pi Men b contributes to make the brown dwarf desert a bit greener.
Acceso Abierto
A sub-Neptune and a non-transiting Neptune-mass companion unveiled by ESPRESSO around the bright late-F dwarf HD 5278 (TOI-130)
(EDP Sciences, 2021-04-14) Sozzetti, A.; Damasso, M.; Bonomo, A. S.; Alibert, Y.; Sousa, S. G.; Adibekyan, V.; Zapatero Osorio, M. R.; González Hernández, J. I.; Barros, S. C. C.; Lillo Box, J.; Stassun, K. G.; Winn, J. N.; Cristiani, S.; Pepe, Francesco; Rebolo, R.; Santos, Nuno C.; Allart, R.; Barclay, T.; Bouchy, F.; Cabral, A.; Ciardi, D. R.; Di Marcantonio, P.; D´Odorico, V.; Ehrenreich, D.; Fausnaugh, M.; Figueira, P.; Haldemann, J.; Jenkins, J. M.; Latham, D. W.; Lavie, B.; Lo Curto, G.; Lovis, C.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Micela, G.; Molaro, P.; Nunes, Nelson J.; Oshagh, M.; Otegi, Jon F.; Pallé, E.; Poretti, E.; Ricker, George; Rodríguez, D.; Seager, S.; Suárez Mascareño, A.; Twicken, J. D.; Udry, S.; Istituto Nazionale di Astrofisica (INAF); Agenzia Spaziale Italiana (ASI); iss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); European Commission (EC); European Research Council (ERC); Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI) http://dx.doi.org/10.13039/501100011033; Sozzetti, A. [0000-0002-7504-365X]; Nunes, N. [0000-0002-3837-6914]; Haldemann, J. [0000-0003-1231-2389]
Context. Transiting sub-Neptune-type planets, with radii approximately between 2 and 4 R⊕, are of particular interest as their study allows us to gain insight into the formation and evolution of a class of planets that are not found in our Solar System. Aims. We exploit the extreme radial velocity (RV) precision of the ultra-stable echelle spectrograph ESPRESSO on the VLT to unveil the physical properties of the transiting sub-Neptune TOI-130 b, uncovered by the TESS mission orbiting the nearby, bright, late F-type star HD 5278 (TOI-130) with a period of Pb = 14.3 days. Methods. We used 43 ESPRESSO high-resolution spectra and broad-band photometry information to derive accurate stellar atmospheric and physical parameters of HD 5278. We exploited the TESS light curve and spectroscopic diagnostics to gauge the impact of stellar activity on the ESPRESSO RVs. We performed separate as well as joint analyses of the TESS photometry and the ESPRESSO RVs using fully Bayesian frameworks to determine the system parameters. Results. Based on the ESPRESSO spectra, the updated stellar parameters of HD 5278 are Teff = 6203 ± 64 K, log g = 4.50 ± 0.11 dex, [Fe/H] = −0.12 ± 0.04 dex, M⋆ = 1.126−0.035+0.036 M⊙, and R⋆ = 1.194−0.016+0.017 R⊙. We determine HD 5278 b’s mass and radius to be Mb = 7.8−1.4+1.5 M⊕ and Rb = 2.45 ± 0.05R⊕. The derived mean density, ϱb = 2.9−0.5+0.6 g cm−3, is consistent with the bulk composition of a sub-Neptune with a substantial (~ 30%) water mass fraction and with a gas envelope comprising ~17% of the measured radius. Given the host brightness and irradiation levels, HD 5278 b is one of the best targetsorbiting G-F primaries for follow-up atmospheric characterization measurements with HST and JWST. We discover a second, non-transiting companion in the system, with a period of Pc = 40.87−0.17+0.18 days and a minimum mass of Mc sin ic = 18.4−1.9+1.8 M⊕. We study emerging trends in parameters space (e.g., mass, radius, stellar insolation, and mean density) of the growing population of transiting sub-Neptunes, and provide statistical evidence for a low occurrence of close-in, 10 − 15M⊕ companions around G-F primaries with Teff ≳ 5500 K.
Acceso Abierto
A super-Earth on a close-in orbit around the M1V star GJ 740 A HADES and CARMENES collaboration
(EDP Sciences, 2021-04-07) Toledo Padrón, B.; Suárez Mascareño, A.; González Hernández, J. I.; Rebolo, R.; Pinamonti, M.; Perger, M.; Scandariato, G.; Damasso, M.; Sozzetti, A.; Moldonado, J.; Desidera, S.; Ribas, I.; Micela, G.; Affer, L.; González Álvarez, E.; Leto, G.; Pagano, I.; Zanmar Sánchez, R.; Giacobbe, P.; Herrero, Enrique; Morales, J. C.; Amado, P. J.; Caballero, J. A.; Quirrenbach, A.; Reiners, A.; Zechmeister, M.; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Generalitat de Catalunya
Context. M-dwarfs have proven to be ideal targets for planetary radial velocity (RV) searches due to their higher planet-star mass contrast, which favors the detection of low-mass planets. The abundance of super-Earth and Earth-like planets detected around this type of star motivates further such research on hosts without reported planetary companions. Aims. The HADES and CARMENES programs are aimed at carrying out extensive searches of exoplanetary systems around M-type stars in the northern hemisphere, allowing us to address, in a statistical sense, the properties of the planets orbiting these objects. In this work, we perform a spectroscopic and photometric study of one of the program stars (GJ 740), which exhibits a short-period RV signal that is compatible with a planetary companion. Methods. We carried out a spectroscopic analysis based on 129 HARPS-N spectra taken over a time span of 6 yr combined with 57 HARPS spectra taken over 4 yr, as well as 32 CARMENES spectra taken during more than 1 yr, resulting in a dataset with a time coverage of 10 yr. We also relied on 459 measurements from the public ASAS survey with a time-coverage of 8 yr, along with 5 yr of photometric magnitudes from the EXORAP project taken in the V, B, R, and I filters to carry out a photometric study. Both analyses were made using Markov chain Monte Carlo simulations and Gaussian process regression to model the activity of the star. Results. We present the discovery of a short-period super-Earth with an orbital period of 2.37756−0.00011+0.00013 d and a minimum mass of 2.96−0.48+0.50 M⊕. We offer an update to the previously reported characterization of the magnetic cycle and rotation period of the star, obtaining values of Prot = 35.563 ± 0.071 d and Pcycle = 2800 ± 150 d. Furthermore, the RV time series exhibits a possibly periodic long-term signal, which might be related to a Saturn-mass planet of ~100 M⊕.
Acceso Abierto
All-sky visible and near infrared space astrometry
(Springer Link, 2021-03-11) Hobbs, D.; Brown, Anthony; Hog, E.; Jordi, C.; Kawata, D.; Tanga, P.; Klioner, S. A.; Sozzetti, A.; Wyrzykowski, L.; Walton, N.; Vallenari, A.; Makarov, V.; Rybizki, J.; Jiménez Esteban, F. M.; Caballero, J. A.; McMillan, P. J.; Secrest, N.; Mor, R.; Andrews, Jeff J.; Zwitter, T.; Chiappini, C.; Fynbo, J. P. U.; Ting, Y. S.; Hestroffer, D.; Lindegren, L.; McArthur, B.; Gouda, N.; Moore, A.; González, O. A.; Vaccari, M.; Hobbs, D. [0000-0002-2696-1366]; Brown, A. [0000-0002-7419-9679]; Sozzetti, A. [0000-0002-7504-365X]; Secrest, N. [0000-0002-4902-8077]
The era of all-sky space astrometry began with the Hipparcos mission in 1989 and provided the first very accurate catalogue of apparent magnitudes, positions, parallaxes and proper motions of 120 000 bright stars at the milliarcsec (or milliarcsec per year) accuracy level. Hipparcos has now been superseded by the results of the Gaia mission. The second Gaia data release contained astrometric data for almost 1.7 billion sources with tens of microarcsec (or microarcsec per year) accuracy in a vast volume of the Milky Way and future data releases will further improve on this. Gaia has just completed its nominal 5-year mission (July 2019), but is expected to continue in operations for an extended period of an additional 5 years through to mid 2024. Its final catalogue to be released ∼ 2027, will provide astrometry for ∼ 2 billion sources, with astrometric precisions reaching 10 microarcsec. Why is accurate astrometry so important? The answer is that it provides fundamental data which underpin much of modern observational astronomy as will be detailed in this White Paper. All-sky visible and Near-InfraRed (NIR) astrometry with a wavelength cutoff in the K-band is not just focused on a single or small number of key science cases. Instead, it is extremely broad, answering key science questions in nearly every branch of astronomy while also providing a dense and accurate visible-NIR reference frame needed for future astronomy facilities.
Acceso Abierto
Atmospheric Rossiter–McLaughlin effect and transmission spectroscopy of WASP-121b with ESPRESSO
(EDP Sciences, 2021-01-22) Borsa, F.; Allart, R.; Casasayas Barris, N.; Tabernero, H. M.; Zapatero Osorio, M. R.; Cristiani, S.; Pepe, Francesco; Rebolo, R.; Santos, Nuno C.; Adibekyan, V.; Bourrier, V.; Demangeon, O. D. S.; Ehrenreich, D.; Pallé, E.; Sousa, S. G.; Lillo Box, J.; Lovis, C.; Micela, G.; Oshagh, M.; Poretti, E.; Sozzetti, A.; Allende Prieto, C.; Alibert, Y.; Amate, M.; Benz, W.; Bouchy, F.; Cabral, A.; Dekker, H.; D´Odorico, V.; Di Marcantonio, P.; Figueira, P.; Genova Santos, R.; González Hernández, J. I.; Lo Curto, G.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Molaro, P.; Nunes, Nelson J.; Riva, M.; Suárez Mascareño, A.; Udry, S.; Zerbi, Filippo M.; Istituto Nazionale di Astrofisica (INAF); Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); European Research Council (ERC); Cabral, A. [0000-0002-9433-871X]; Adibekyan, V. [0000-0002-0601-6199]; Santos, N. [0000-0003-4422-2919]; Nunes, N. [0000-0002-3837-6914]; Sozzetti, A. [0000-0002-7504-365X]; Suarez Mascareño, A. [0000-0002-3814-5323]
Context. Ultra-hot Jupiters are excellent laboratories for the study of exoplanetary atmospheres. WASP-121b is one of the most studied; many recent analyses of its atmosphere report interesting features at different wavelength ranges. Aims. In this paper we analyze one transit of WASP-121b acquired with the high-resolution spectrograph ESPRESSO at VLT in one-telescope mode, and one partial transit taken during the commissioning of the instrument in four-telescope mode. Methods. We take advantage of the very high S/N data and of the extreme stability of the spectrograph to investigate the anomalous in-transit radial velocity curve and study the transmission spectrum of the planet. We pay particular attention to the removal of instrumental effects, and stellar and telluric contamination. The transmission spectrum is investigated through single-line absorption and cross-correlation with theoretical model templates. Results. By analyzing the in-transit radial velocities we were able to infer the presence of the atmospheric Rossiter–McLaughlin effect. We measured the height of the planetary atmospheric layer that correlates with the stellar mask (mainly Fe) to be 1.052 ± 0.015 Rp and we also confirmed the blueshift of the planetary atmosphere. By examining the planetary absorption signal on the stellar cross-correlation functions we confirmed the presence of a temporal variation of its blueshift during transit, which could be investigated spectrum-by-spectrum thanks to the quality of our ESPRESSO data. We detected significant absorption in the transmission spectrum for Na, H, K, Li, Ca II, and Mg, and we certified their planetary nature by using the 2D tomographic technique. Particularly remarkable is the detection of Li, with a line contrast of ~0.2% detected at the 6σ level. With the cross-correlation technique we confirmed the presence of Fe I, Fe II, Cr I, and V I. Hα and Ca II are present up to very high altitudes in the atmosphere (~1.44 Rp and ~2 Rp, respectively), and also extend beyond the transit-equivalent Roche lobe radius of the planet. These layers of the atmosphere have a large line broadening that is not compatible with being caused by the tidally locked rotation of the planet alone, and could arise from vertical winds or high-altitude jets in the evaporating atmosphere.
Acceso Abierto
Broadband transmission spectroscopy of HD 209458b with ESPRESSO: evidence for Na, TiO, or both
(EDP Sciences, 2020-12-01) Santos, Nuno C.; Cristo, E.; Demangeon, O. D. S.; Oshagh, M.; Allart, R.; Barros, S. C. C.; Borsa, F.; Bourrier, V.; Casasayas Barris, N.; Ehrenreich, D.; Faria, J. P.; Figueira, P.; Martins, J. H. C.; Micela, G.; Pallé, E.; Sozzetti, A.; Tabernero, H. M.; Zapatero Osorio, M. R.; Pepe, Francesco; Cristiani, S.; Rebolo, R.; Adibekyan, V.; Allende Prieto, C.; Alibert, Y.; Bouchy, F.; Cabral, A.; Dekker, H.; Di Marcantonio, P.; D´Odorico, V.; Dumusque, X.; González Hernández, J. I.; Lavie, B.; Lo Curto, G.; Lovis, C.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Molaro, P.; Nunes, Nelson J.; Poretti, E.; Rivas, M.; Sousa, S. G.; Suárez Mascareño, A.; Udry, S.; Fundacao para a Ciencia e a Tecnologia (FCT); Istituto Nazionale di Astrofisica (INAF); European Research Council (ERC); Agencia Estatal de Investigación (AEI); 0000-0003-4422-2919; 0000-0001-5992-7589; 0000-0001-7918-0355; 0000-0002-0715-8789; 0000-0003-0987-1593
Context. The detection and characterization of exoplanet atmospheres is currently one of the main drivers pushing the development of new observing facilities. In this context, high-resolution spectrographs are proving their potential and showing that high-resolution spectroscopy will be paramount in this field. Aims. We aim to make use of ESPRESSO high-resolution spectra, which cover two transits of HD 209458b, to probe the broadband transmission optical spectrum of the planet. Methods. We applied the chromatic Rossiter–McLaughin method to derive the transmission spectrum of HD 209458b. We compared the results with previous HST observations and with synthetic spectra. Results. We recover a transmission spectrum of HD 209458b similar to the one obtained with HST data. The models suggest that the observed signal can be explained by only Na, only TiO, or both Na and TiO, even though none is fully capable of explaining our observed transmission spectrum. Extra absorbers may be needed to explain the full dataset, though modeling approximations and observational errors can also be responsible for the observed mismatch. Conclusions. Using the chromatic Rossiter–McLaughlin technique, ESPRESSO is able to provide broadband transmission spectra of exoplanets from the ground, in conjunction with space-based facilities, opening good perspectives for similar studies of other planets.
Acceso Abierto
Characterization of the K2-38 planetary system Unraveling one of the densest planets known to date
(EDP Sciences, 2020-09-14) Toledo Padrón, B.; Lovis, C.; Suárez Mascareño, A.; Barros, S. C. C.; González Hernández, J. I.; Sozzetti, A.; Bouchy, F.; Zapatero Osorio, M. R.; Rebolo, R.; Cristiani, S.; Pepe, Francesco; Santos, Nuno C.; Sousa, S. G.; Tabernero, H. M.; Lillo Box, J.; Bossini, D.; Adibekyan, V.; Allart, R.; Damasso, M.; D´Odorico, V.; Figueira, P.; Lavie, B.; Lo Curto, G.; Mehner, A.; Micela, G.; Modigliani, A.; Nunes, Nelson J.; Pallé, E.; Abreu, M.; Affolter, M.; Alibert, Y.; Aliverti, M.; Allende Prieto, C.; Alves, D.; Amate, M.; Ávila, G.; Baldini, V.; Bandy, T.; Benatti, S.; Benz, W.; Bianco, A.; Broeg, C.; Cabral, A.; Calderone, G.; Cirami, R.; Coelho, J.; Conconi, P.; Coretti, I.; Cumani, C.; Cupani, G.; Deiries, S.; Dekker, H.; Delabre, B.; Demangeon, O. D. S.; Di Marcantonio, P.; Ehrenreich, D.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; Hughes, I.; Iwert, O.; Knudstrup, J.; Landoni, M.; Lizon, Jean Louis; Maire, C.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Molaro, P.; Monteiro, M. J. P. F. G.; Monteiro, M. A.; Moschetti, M.; Mueller, E.; Oggioni, L.; Oliveira, António; Rivas, M.; Santana Tschudi, S.; Santin, P.; Santos, Pedro; Segovia, A.; Sosnowska, D.; Spanò, P.; Tenegi, F.; Udry, S.; Zanutta, A.; Zerbi, Filippo M.; Fundacion La Caixa; Swiss National Science Foundation (SNSF); European Research Council (ERC); Fundacao para a Ciencia e a Tecnologia (FCT); Ministerio de Ciencia e Innovación (MICINN); 0000-0001-8160-5076; 0000-0003-0987-1593; 0000-0001-5664-2852; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. An accurate characterization of the known exoplanet population is key to understanding the origin and evolution of planetary systems. Determining true planetary masses through the radial velocity (RV) method is expected to experience a great improvement thanks to the availability of ultra-stable echelle spectrographs. Aims. We took advantage of the extreme precision of the new-generation echelle spectrograph ESPRESSO to characterize the transiting planetary system orbiting the G2V star K2-38 located at 194 pc from the Sun with V similar to 11.4. This system is particularly interesting because it could contain the densest planet detected to date. Methods. We carried out a photometric analysis of the available K2 photometric light curve of this star to measure the radius of its two known planets, K2-38b and K2-38c, with P-b = 4.01593 +/- 0.00050 d and P-c = 10.56103 +/- 0.00090 d, respectively. Using 43 ESPRESSO high-precision RV measurements taken over the course of 8 months along with the 14 previously published HIRES RV measurements, we modeled the orbits of the two planets through a Markov chain Monte Carlo analysis, significantly improving their mass measurements. Results. Using ESPRESSO spectra, we derived the stellar parameters, T-eff = 5731 +/- 66, log g = 4.38 +/- 0.11 dex, and [Fe/H] = 0 :26 +/- 0.05 dex, and thus the mass and radius of K2-38, M-star = 1.03(-0.02)(+0.04) M-circle plus and R-circle plus = 1.06+0:09 0:06 R-circle plus. We determine new values for the planetary properties of both planets. We characterize K2-38b as a super-Earth with R-P = 1.54 +/- 0.14 R-circle plus and M-p = 7.3(-1.0)(+1:1) M-circle plus, and K2-38c as a sub-Neptune with RP = 2.29 +/- 0.26 R-circle plus and M-p = 8.3(-1.3)(+1:3) M (circle plus). Combining the radius and mass measurements, we derived a mean density of rho(p) = 11.0(-2.8)(+4:1) g cm(-3) for K2-38b and rho(p) = 3.8+1:8 1:1 g cm(-3) for K2-38c, confirming K2-38b as one of the densest planets known to date. Conclusions. The best description for the composition of K2-38b comes from an iron-rich Mercury-like model, while K2-38c is better described by a rocky-model with H2 envelope. The maximum collision stripping boundary shows how giant impacts could be the cause for the high density of K2-38b. The irradiation received by each planet places them on opposite sides of the radius valley. We find evidence of a long-period signal in the RV time-series whose origin could be linked to a 0.25-3 MJ planet or stellar activity.
Acceso Abierto
ESPRESSO at VLT On-sky performance and first results
(EDP Sciences, 2021-01-19) Pepe, Francesco; Cristiani, S.; Rebolo, R.; Santos, Nuno C.; Dekker, H.; Cabral, A.; Di Marcantonio, P.; Figueira, P.; Lo Curto, G.; Lovis, C.; Mayor, M.; Mégevand, D.; Molaro, P.; Riva, M.; Zapatero Osorio, M. R.; Amate, M.; Manescau, A.; Pasquini, L.; Zerbi, Filippo M.; Adibekyan, V.; Abreu, M.; Affolter, M.; Alibert, Y.; Aliverti, M.; Allart, R.; Allende Prieto, C.; Álvarez, D.; Alves, D.; Ávila, G.; Baldini, V.; Bandy, T.; Barros, S. C. C.; Benz, W.; Bianco, A.; Borsa, F.; Bourrier, V.; Bouchy, F.; Broeg, C.; Calderone, G.; Cirami, R.; Coelho, J.; Conconi, P.; Coretti, I.; Cumani, C.; Cupani, G.; D´Odorico, V.; Damasso, M.; Deiries, S.; Delabre, B.; Demangeon, O. D. S.; Dumusque, X.; Ehrenreich, D.; Faria, J. P.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; González Hernández, J. I.; Hughes, I.; Iwert, O.; Kerber, F.; Knudstrup, J.; Landoni, M.; Lavie, B.; Lillo Box, J.; Lizon, Jean Louis; Maire, C.; Martins, C. J. A. P.; Mehner, A.; Micela, G.; Modigliani, A.; Monteiro, M. A.; Monteiro, M. J. P. F. G.; Moschetti, M.; Murphy, M. T.; Nunes, Nelson J.; Oggioni, L.; Oliveira, António; Oshagh, M.; Pallé, E.; Pariani, G.; Poretti, E.; Rasilla, J. L.; Rebordao, J.; Redaelli, E.; Santana Tschudi, S.; Santin, P.; Santos, Pedro; Ségransan, D.; Schmidt, T. M.; Segovia, A.; Sosnowska, D.; Sozzetti, A.; Sousa, S. G.; Spanò, P.; Suárez Mascareño, A.; Tabernero, H. M.; Tenegi, F.; Udry, S.; Zanutta, A.; Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); European Research Council (ERC); Agencia Estatal de Investigación (AEI); Australian Research Council; 0000-0002-9433-871X; 0000-0003-0513-8116; 0000-0002-4339-0550; 0000-0002-6728-244X; 0000-0003-2434-3625; 0000-0002-7504-365X; 0000-0002-7040-5498; 0000-0003-4422-2919; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. ESPRESSO is the new high-resolution spectrograph of ESO’s Very Large Telescope (VLT). It was designed for ultra-high radial-velocity (RV) precision and extreme spectral fidelity with the aim of performing exoplanet research and fundamental astrophysical experiments with unprecedented precision and accuracy. It is able to observe with any of the four Unit Telescopes (UTs) of the VLT at a spectral resolving power of 140 000 or 190 000 over the 378.2 to 788.7 nm wavelength range; it can also observe with all four UTs together, turning the VLT into a 16 m diameter equivalent telescope in terms of collecting area while still providing a resolving power of 70 000. Aims. We provide a general description of the ESPRESSO instrument, report on its on-sky performance, and present our Guaranteed Time Observation (GTO) program along with its first results. Methods. ESPRESSO was installed on the Paranal Observatory in fall 2017. Commissioning (on-sky testing) was conducted between December 2017 and September 2018. The instrument saw its official start of operations on October 1, 2018, but improvements to the instrument and recommissioning runs were conducted until July 2019. Results. The measured overall optical throughput of ESPRESSO at 550 nm and a seeing of 0.65″ exceeds the 10% mark under nominal astroclimatic conditions. We demonstrate an RV precision of better than 25 cm s−1 during a single night and 50 cm s−1 over several months. These values being limited by photon noise and stellar jitter shows that the performance is compatible with an instrumental precision of 10 cm s−1. No difference has been measured across the UTs, neither in throughput nor RV precision. Conclusions. The combination of the large collecting telescope area with the efficiency and the exquisite spectral fidelity of ESPRESSO opens a new parameter space in RV measurements, the study of planetary atmospheres, fundamental constants, stellar characterization, and many other fields.
Acceso Abierto
ESPRESSO high-resolution transmission spectroscopy of WASP-76 b
(EDP Sciences, 2021-02-19) Tabernero, H. M.; Zapatero Osorio, M. R.; Allart, R.; Borsa, F.; Casasayas Barris, N.; Demangeon, O. D. S.; Ehrenreich, D.; Lillo Box, J.; Lovis, C.; Pallé, E.; Sousa, S. G.; Rebolo, R.; Santos, Nuno C.; Pepe, Francesco; Cristiani, S.; Adibekyan, V.; Allende Prieto, C.; Alibert, Y.; Barros, S. C. C.; Bouchy, F.; Bourrier, V.; D´Odorico, V.; Dumusque, X.; Faria, J. P.; Figueira, P.; Genova Santos, R.; González Hernández, J. I.; Hojjatpanah, S.; Lo Curto, G.; Lavie, B.; Martins, C. J. A. P.; Martins, J. H. C.; Mehner, A.; Micela, G.; Molaro, P.; Nunes, Nelson J.; Poretti, E.; Seidel, J. V.; Sozzetti, A.; Suárez Mascareño, A.; Udry, S.; Aliverti, M.; Affolter, M.; Alves, D.; Amate, M.; Ávila, G.; Bandy, T.; Benz, W.; Bianco, A.; Broeg, C.; Cabral, A.; Conconi, P.; Coelho, J.; Cumani, C.; Deiries, S.; Dekker, H.; Delabre, B.; Fragoso, A.; Genoni, M.; Genolet, L.; Hughes, I.; Knudstrup, J.; Kerber, F.; Landoni, M.; Lizon, Jean Louis; Maire, C.; Manescau, A.; Di Marcantonio, P.; Mégevand, D.; Monteiro, M.; Moschetti, M.; Mueller, E.; Modigliani, A.; Oggioni, L.; Oliveira, António; Pariani, G.; Pasquini, L.; Rasilla, J. L.; Redaelli, E.; Riva, M.; Santana Tschudi, S.; Santin, P.; Santos, Pedro; Segovia, A.; Sosnowska, D.; Spanò, P.; Tenegi, F.; Iwert, O.; Zanutta, A.; Zerbi, Filippo M.; European Research Council (ERC); Fundacao para a Ciencia e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); Istituto Nazionale di Astrofisica (INAF); Cabral, A. [0000-0002-9433-871X]; Monteiro, M. J. [0000-0003-0513-8116]; Coelho, F. M. [0000-0002-4339-0550]; Faria, J. [0000-0002-6728-244X]; Santos, N. [0000-0003-4422-2919]
Aims. We report on ESPRESSO high-resolution transmission spectroscopic observations of two primary transits of the highly irradiated, ultra-hot Jupiter-sized planet, WASP-76b. We investigated the presence of several key atomic and molecular features of interest that may reveal the atmospheric properties of the planet. Methods. We extracted two transmission spectra of WASP-76b with R ≈ 140 000 using a procedure that allowed us to process the full ESPRESSO wavelength range (3800–7880 Å) simultaneously. We observed that at a high signal-to-noise ratio, the continuum of ESPRESSO spectra shows ‘wiggles’, which are likely caused by an interference pattern outside the spectrograph. To search for the planetary features, we visually analysed the extracted transmission spectra and cross-correlated the observations against theoretical spectra of different atomic and molecular species. Results. The following atomic features are detected: Li I, Na I, Mg I, Ca II, Mn I, K I, and Fe I. All are detected with a confidence level between 9.2 σ (Na I) and 2.8 σ (Mg I). We did not detect the following species: Ti I, Cr I, Ni I, TiO, VO, and ZrO. We impose the following 1 σ upper limits on their detectability: 60, 77, 122, 6, 8, and 8 ppm, respectively. Conclusions. We report the detection of Li I on WASP-76b for the first time. In addition, we confirm the presence of Na I and Fe I as previously reported in the literature. We show that the procedure employed in this work can detect features down to the level of ~0.1% in the transmission spectrum and ~10 ppm by means of a cross-correlation method. We discuss the presence of neutral and singly ionised features in the atmosphere of WASP-76b.
Acceso Abierto
ESPRESSO highlights the binary nature of the ultra-metal-poor giant HE 0107−5240.
(EDP Sciences, 2020-01-22) Bonifacio, P.; Molaro, P.; Adibekyan, V.; Aguado, D.; Alibert, Y.; Allende Prieto, C.; Caffau, E.; Cristiani, S.; Cupani, G.; Di Marcantonio, P.; D´Odorico, V.; Ehrenreich, D.; Figueira, P.; Genova, R.; González Hernández, J. I.; Lo Curto, G.; Lovis, C.; Martins, C. J. A. P.; Mehner, A.; Micela, G.; Monaco, L.; Nunes, Nelson J.; Pepe, Francesco; Poretti, E.; Rebolo, R.; Santos, Nuno C.; Saviane, I.; Sousa, S. G.; Sozzetti, A.; Suárez Mascareño, A.; Udry, S.; Zapatero Osorio, M. R.; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Fundacao para a Ciencia e a Tecnologia (FCT); European Research Council (ERC); European Research Council (ERC); Molaro, P. [0000-0002-0571-4163]; Monaco, L. [0000-0002-3148-9836]; Nunes, N. J. [0000-0002-3837-6914]; Suarez Mascareño, A. [0000-0002-3814-5323]; Aguado, D. [0000-0001-5200-3973]; González Hernández, J. I. [0000-0002-0264-7356]; Adibekyan, V. [0000-0002-0601-6199]; Zapatero Osorio, M. R. [0000-0001-5664-2852]; Figueira, P. [0000-0001-8504-283X]; Sozzetti, A. [0000-0002-7504-365X]; Santos, N. [0000-0003-4422-2919]; Cupani, G. [0000-0002-6830-9093]; Martins, C. J. A. P. [0000-0002-4886-9261]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The vast majority of the known stars of ultra low metallicity ([Fe/H] < −4.5) are known to be enhanced in carbon, and belong to the “low-carbon band” (A(C) = log(C/H)+12 ≤ 7.6). It is generally, although not universally, accepted that this peculiar chemical composition reflects the chemical composition of the gas cloud out of which these stars were formed. The first ultra-metal-poor star discovered, HE 0107−5240, is also enhanced in carbon and belongs to the “low-carbon band”. It has recently been claimed to be a long-period binary, based on radial velocity measurements. It has also been claimed that this binarity may explain its peculiar composition as being due to mass transfer from a former AGB companion. Theoretically, low-mass ratios in binary systems are much more favoured amongst Pop III stars than they are amongst solar-metallicity stars. Any constraint on the mass ratio of a system of such low metallicity would shed light on the star formation mechanisms in this metallicity regime. Aims. We acquired one high precision spectrum with ESPRESSO in order to check the reality of the radial velocity variations. In addition we analysed all the spectra of this star in the ESO archive obtained with UVES to have a set of homogenously measured radial velocities. Methods. The radial velocities were measured using cross correlation against a synthetic spectrum template. Due to the weakness of metallic lines in this star, the signal comes only from the CH molecular lines of the G-band. Results. The measurement obtained in 2018 from an ESPRESSO spectrum demonstrates unambiguously that the radial velocity of HE 0107−5240 has increased from 2001 to 2018. Closer inspection of the measurements based on UVES spectra in the interval 2001–2006 show that there is a 96% probability that the radial velocity correlates with time, hence the radial velocity variations can already be suspected from the UVES spectra alone. Conclusions. We confirm the earlier claims of radial velocity variations in HE 0107−5240. The simplest explanation of such variations is that the star is indeed in a binary system with a long period. The nature of the companion is unconstrained and we consider it is equally probable that it is an unevolved companion or a white dwarf. Continued monitoring of the radial velocities of this star is strongly encouraged.
Acceso Abierto
Fundamental physics with ESPRESSO: Towards an accurate wavelength calibration for a precision test of the fine-structure constant
(EDP Sciences, 2021-02-19) Schmidt, T. M.; Molaro, P.; Murphy, M. T.; Lovis, C.; Cupani, G.; Cristiani, S.; Pepe, Francesco; Rebolo, R.; Santos, Nuno C.; Abreu, M.; Adibekyan, V.; Alibert, Y.; Aliverti, M.; Allart, R.; Allende Prieto, C.; Alves, D.; Baldini, V.; Broeg, C.; Cabral, A.; Calderone, G.; Cirami, R.; Coelho, J.; Coretti, I.; D´Odorico, V.; Di Marcantonio, P.; Ehrenreich, D.; Figueira, P.; Genoni, M.; Génova Santos, R.; González Hernández, J. I.; Kerber, F.; Londoni, M.; Leite, A. C. O.; Louis Lizon, J.; Lo Curto, G.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Micela, G.; Modigliani, A.; Monteiro, M.; Monteiro, M. J. P. F. G.; Mueller, E.; Nunes, Nelson J.; Oggioni, L.; Oliveira, António; Pariani, G.; Pasquini, L.; Redaelli, E.; Riva, M.; Santos, Pedro; Sosnowska, D.; Sousa, S. G.; Sozzetti, A.; Suárez Mascareño, A.; Udry, S.; Zapatero Osorio, M. R.; Zerbi, Filippo M.; Istituto Nazionale di Astrofisica (INAF); Australian Research Council (ARC); Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); European Research Council (ERC); Schmidt, T. M. [0000-0002-4833-7273]; Molaro, P. [0000-0002-0571-4163]; Murphy, M. T. [0000-0002-7040-5498]; Cristiani, S. [0000-0002-2115-5234]; Pepe, F. A. [0000-0002-9815-773X]; Rebolo, R. [0000-0003-3767-7085]
Observations of metal absorption systems in the spectra of distant quasars allow one to constrain a possible variation of the fine-structure constant throughout the history of the Universe. Such a test poses utmost demands on the wavelength accuracy and previous studies were limited by systematics in the spectrograph wavelength calibration. A substantial advance in the field is therefore expected from the new ultra-stable high-resolution spectrograph ESPRESSO, which was recently installed at the VLT. In preparation of the fundamental physics related part of the ESPRESSO GTO program, we present a thorough assessment of the ESPRESSO wavelength accuracy and identify possible systematics at each of the different steps involved in the wavelength calibration process. Most importantly, we compare the default wavelength solution, which is based on the combination of Thorium-Argon arc lamp spectra and a Fabry-Pérot interferometer, to the fully independent calibration obtained from a laser frequency comb. We find wavelength-dependent discrepancies of up to 24 m s−1. This substantially exceeds the photon noise and highlights the presence of different sources of systematics, which we characterize in detail as part of this study. Nevertheless, our study demonstrates the outstanding accuracy of ESPRESSO with respect to previously used spectrographs and we show that constraints of a relative change of the fine-structure constant at the 10−6 level can be obtained with ESPRESSO without being limited by wavelength calibration systematics.
Acceso Abierto
Gaia Early Data Release 3 Acceleration of the Solar System from Gaia astrometry
(EDP Sciences, 2021-04-28) Klioner, S. A.; Mignard, F.; Lindegren, L.; Bastian, U.; McMillan, P. J.; Hernández, J.; Hobbs, D.; Ramos Lerate, M.; Biermann, M.; Bombrun, A.; De Torres, A.; Becciani, U.; Peñalosa Esteller, X.; Hauser, M.; Dell´Oro, A.; Viala, Y.; Brouillet, N.; Taris, F.; Bellas Velidis, I.; Blomme, R.; Pauwels, T.; Brugaletta, E.; Fabricius, C.; Haywood, M.; Eyer, L.; Mints, A.; Souami, D.; Mowlavi, N.; Lindstrom, H. E. P.; Portell, J.; Aerts, C.; Bernet, M.; Hladczuk, N.; De Souza, R.; Casamiquela, L.; Soubiran, C.; Fouesneau, M.; Cheek, N.; Anglada Varela, E.; Madrero Pardo, P.; Lorca, A.; Rybizki, J.; Drimmel, R.; Chemin, L.; Managau, S.; Pineau, F. X.; Heiter, U.; Panem, C.; Ducourant, C.; Marchal, O.; Balog, Z.; Spoto, F.; Fraile, E.; Gosset, E.; Vanel, O.; Steele, I. A.; Delgado, A.; Mastrobuono Battisti, A.; Smith, M.; Burgess, P. W.; Vecchiato, A.; Morbidelli, R.; Riclet, F.; Charlot, P.; Baker, S. G.; Pawlak, M.; Bucciarelli, B.; Carrasco, J. M.; Marinoni, S.; Leclerc, N.; Lebzelter, T.; Sordo, R.; Gilmore, G.; Zhao, H.; Fedorets, G.; Manteiga, M.; García Reinaldos, M.; Mulone, A. F.; Giacobbe, P.; Thuillot, W.; Arenou, F.; Clementini, G.; Osborne, Paul; Poggio, E.; Jevardat de Fombelle, G.; Semeux, D.; De Ridder, J.; Penttilä, A.; De Teodoro, P.; Lattanzi, M. G.; Montegriffo, P.; Muinonen, K.; Marshall, D. J.; Hatzidimitriou, D.; Rainer, M.; Barstow, M. A.; Gerlach, E.; García Lario, P.; Szabados, L.; Le Fustec, Y.; Garabato, D.; Szegedi Elek, E.; Bellazzini, M.; Bramante, L.; Galluccio, L.; González Santamaría, I.; Berthier, J.; Brown, A. G. A.; Baudesson Stella, A.; Cowell, S.; Abbas, U.; Santoveña, R.; Mora, A.; Sartoretti, P.; Anderson, R. I.; Álvarez Cid Fuentes, J.; Reylé, C.; Barache, C.; Delgado, H. E.; García Torres, M.; Luri, X.; Jonker, P. G.; Altavilla, G.; Thévenin, F.; Bianchi, L.; Eappachen, D.; Robichon, N.; Castro Sampol, P.; David, M.; Siopis, C.; Robin, C.; Taylor, M. B.; Cánovas, H.; Recio Blanco, A.; Van Reeven, W.; Girona, S.; Fernique, P.; Teyssier, D.; Molnár, L.; Burlacu, A.; Altmann, M.; Pagani, C.; Salguero, E.; De Luise, F.; Stephenson, C. A.; Fernández Hernández, J.; Ségransan, D.; Audard, Marc; Schultheis, M.; Fabrizio, M.; González Vidal, J. J.; Haigron, R.; Rowell, N.; Ramos, P.; Sanna, N.; Balaguer Núñez, L.; Randich, S.; Harrison, D. L.; Messina, S.; Chaoul, Laurence; Cropper, M.; Muraveva, T.; Kochoska, A.; Roegiers, T.; Blanco Cuaresma, S.; Cooper, W. J.; Tonello, N.; Carnerero, M. I.; Nienartowicz, K.; Lobel, A.; Zwitter, T.; Sozzetti, A.; Segol, M.; Comoretto, G.; Rybicki, K. A.; Cancelliere, R.; Gai, M.; Fouron, C.; Holl, B.; Bressan, A.; Ragaini, S.; Abreu Aramburu, A.; Ordénovic, C.; Torra, F.; Giuffrida, G.; Bartolomé, S.; Orrù, G.; Bauchet, N.; Löffler, W.; Van Dillen, E.; Del Peloso, E. F.; Guerrier, A.; Chiavassa, A.; Geyer, R.; Siebert, A.; Di Stefano, E.; Khanna, S.; Fienga, A.; Marconi, M.; Morris, D.; Masip, A.; Diakite, S.; Steidelmüller, H.; Gavras, P.; Martín Fleitas, J. M.; Yoldas, A.; Julbe, F.; Liao, S.; De Laverny, P.; Yvard, P.; Helmi, A.; Crifo, F.; Babusiaux, C.; Murphy, C. P.; Millar, N. R.; Barbato, D.; Sciacca, E.; Granvik, M.; Barros, M.; Spagna, A.; Lister, T. A.; Lanzafame, A. C.; Breedt, E.; Nicolas, C.; Esquej, P.; Jean Antonie Piccolo, A.; Mazeh, T.; Osinde, J.; Busonero, D.; Zurbach, C.; Guerra, R.; Faigler, S.; Riello, M.; Caffau, E.; Sánchez Giménez, V.; Karbevska, L.; Sarro, L. M.; Siltala, L.; Prsa, A.; Dapergolas, A.; Le Campion, J. F.; Carry, B.; Huckle, H. E.; Muñoz, D.; Rixon, G.; Hodgkin, S. T.; De March, R.; Messineo, M.; Guiraud, J.; Walton, N. A.; Mor, R.; Kervella, P.; Carballo, R.; Gómez, A.; Vaillant, M.; Del Pozo, E.; Solitro, F.; Cellino, A.; Musella, I.; Fragkoudi, F.; Franke, F.; Castro Ginard, A.; Delchambre, L.; Utrilla, E.; Aguado, J. J.; Kordopatis, G.; Janßen, Katja; Panuzzo, P.; Martin Polo, L.; Poujoulet, E.; Royer, F.; Siddiqui, H. I.; Sahlmann, J.; Marocco, F.; Krone Martins, A.; Hestroffer, D.; Sagristà Sellés, A.; Halbwachs, J. L.; Masana, E.; Marchant, J. M.; Hambly, N. C.; Panahi, A.; Jordi, C.; Lecoeur Taibi, I.; Slezak, E.; Pourbaix, D.; Figueras, F.; Michalik, D.; Gracia Abril, G.; Evans, D. W.; Ripepi, V.; Castellani, M.; Romero Gómez, M.; Alves, J.; Massari, D.; Rimoldini, L.; Samaras, N.; Souchay, J.; Gutiérrez Sánchez, R.; Benson, K.; Süveges, M.; Crowley, C.; Busso, G.; Frémat, Y.; Poretti, E.; David, P.; Plachy, E.; Torra, J.; Leccia, S.; Racero, E.; Piersimoni, A. M.; Creevey, O. L.; Wyrzykowski, L.; Cantat Gaudin, T.; Livanou, E.; Lammers, U.; Ajaj, M.; Robin, A. C.; Segovia, J. C.; Richards, P. J.; Noval, L.; Davidson, M.; Mann, R. G.; Tanga, P.; Bertone, S.; Smart, R. L.; Molinaro, R.; Damerdji, Y.; Juaristi Campillo, J.; Bouquillon, S.; Delisle, J. B.; Pulone, L.; Carlucci, T.; Antoja, T.; Sadowski, G.; García Gutierrez, A.; Van Leeuwen, F.; Pailler, F.; De Angeli, F.; Licata, E.; Vallenari, A.; Castañeda, J.; Butkevich, A. G.; Álvarez, M. A.; Rohrbasser, L.; Buzzi, R.; Riva, A.; Pancino, E.; Re Fiorentin, P.; Roux, W.; Molina, D.; Bailer Jones, C. A. L.; Palaversa, L.; Moitinho, A.; Weiler, M.; Jasniewicz, G.; Zucker, S.; Dolding, C.; Salgado, J.; De Bruijne, J. H. J.; Guy, L. P.; Pagano, I.; Bassilana, J. L.; Wevers, T.; Raiteri, C. M.; Palicio, P. A.; Accart, S.; Fabre, C.; Katz, D.; Teixeira, R.; Rambaux, N.; Unger, N.; Tauran, G.; Marrese, P. M.; Seabroke, G. M.; Hidalgo, S. L.; González Núñez, J.; Jordan, S.; Di Matteo, P.; Dafonte, C.; Crosta, M.; Solano, Enrique; Bossini, D.; Roelens, M.; Balbinot, E.; Prusti, T.; Voutsinas, S.; Garofalo, A.; Boch, T.; Plum, G.; Marcos Santos, M. M. S.; Turon, C.; Jansen, F.; Enke, H.; Bakker, J.; Morel, T.; Ulla, A.; Holland, G.; Van Leeuwen, M.; Regibo, S.; Hilger, T.; Hutton, A.; Diener, C.; Zorec, J.; Lebreton, Y.; Andrae, R.; Cornez, T.; Vicente, D.; Baines, D.; Sarasso, M.; Forderung der wissenschaftlichen Forschung (FWF); Belgian federal Science Policy Office (BELSPO); Hertha Firnberg Programme; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Comite Francais d'Evaluation de la Cooperation Universitaire et Scientifique avec le Bresil (COFECUB); National Natural Science Foundation of China (NSFC); China Scholarship Council (CSC); European Commission (EC); European Research Council (ERC); Hungarian National Research, Development, and Innovation Office (NKFIH); Science Foundation Ireland (SFI); Israel Science Foundation (ISF); Agenzia Spaziale Italiana (ASI); Istituto Nazionale di Astrofisica (INAF); Netherlands Research School for Astronomy (NOVA); Fundacao para a Ciencia e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); European Space Agency (ESA); Centre National D'Etudes Spatiales (CNES); Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR); Narodowe Centrum Nauki (NCN); Slovenian Research Agency; Swedish National Space Agency (SNSA); United Kingdom Science and Technology Facilities Council (STFC); Universitat de Barcelona (UB); Generalitat de Catalunya; Xunta de Galicia; Deliste, J. B. [0000-0001-5844-9888]; Sozzeti, A. [0000-0002-7504-365X]; Unidad de Excelencia Científica María de Maeztu Instituto de Ciencias del Cosmos Universidad de Barcelona, MDM-2014-0369; Centro de Excelencia Científica Severo Ochoa, Instituto de Ciencias del Cosmos de la Universidad de Barcelona, SEV2015-0493
Context. Gaia Early Data Release 3 (Gaia EDR3) provides accurate astrometry for about 1.6 million compact (QSO-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions. Aims. The proper motions of QSO-like sources are used to reveal a systematic pattern due to the acceleration of the solar systembarycentre with respect to the rest frame of the Universe. Apart from being an important scientific result by itself, the acceleration measured in this way is a good quality indicator of the Gaia astrometric solution. Methods. Theeffect of the acceleration was obtained as a part of the general expansion of the vector field of proper motions in vector spherical harmonics (VSH). Various versions of the VSH fit and various subsets of the sources were tried and compared to get the most consistent result and a realistic estimate of its uncertainty. Additional tests with the Gaia astrometric solution were used to get a better idea of the possible systematic errors in the estimate. Results. Our best estimate of the acceleration based on Gaia EDR3 is (2.32 ± 0.16) × 10−10 m s−2 (or 7.33 ±0.51 km s−1 Myr−1) towards α = 269.1° ± 5.4°, δ = −31.6° ± 4.1°, corresponding to a proper motion amplitude of 5.05 ±0.35 μas yr−1. This is in good agreement with the acceleration expected from current models of the Galactic gravitational potential. We expect that future Gaia data releases will provide estimates of the acceleration with uncertainties substantially below 0.1 μas yr−1.
Acceso Abierto
Gaia Early Data Release 3 Structure and properties of the Magellanic Clouds
(EDP Sciences, 2021-04-28) Luri, X.; Chemin, L.; Clementini, G.; Delgado, H. E.; McMillan, P. J.; Romero Gómez, M.; Balbinot, E.; Castro Ginard, A.; Mor, R.; Ripepi, V.; Sarro, L. M.; Delchambre, L.; Guerra, R.; Lobel, A.; Kochoska, A.; De March, R.; Gracia Abril, G.; Gilmore, G.; Carry, B.; Robin, A. C.; Mints, A.; Vecchiato, A.; Kruszynska, K.; Palaversa, L.; Khanna, S.; Jonker, P. G.; Manteiga, M.; Vicente, D.; Dell´Oro, A.; Del Peloso, E. F.; Bartolomé, S.; Destroffer, D.; Segol, M.; Bernet, M.; Murphy, C. P.; Martín Fleitas, J. M.; Wyrzykowski, L.; Guy, L. P.; Managau, S.; Siopis, C.; Esquej, P.; García Gutierrez, A.; Lecoeur Taibi, I.; Diakite, S.; Muinonen, K.; Leclerc, N.; Thuillot, W.; Ulla, A.; Cowell, S.; Osinde, J.; Steidelmüller, H.; Fedorets, G.; Kostrzewa Rutkowska, Z.; Pulone, L.; Comoretto, G.; Voutsinas, S.; Santoveña, R.; Richards, P. J.; Fabrizio, M.; Riva, A.; Julbe, F.; Rybizki, J.; Audard, Marc; Musella, I.; Altavilla, G.; Smith, M.; Muñoz, D.; Mazeh, T.; Giacobbe, P.; Carballo, R.; Piersimoni, A. M.; Sahlmann, J.; Mastrobuono Battisti, A.; Lindegren, L.; Barstow, M. A.; Masana, E.; Stephenson, C. A.; Biermann, M.; Muraveva, T.; Rowell, N.; Hobbs, D.; Marrese, P. M.; Boch, T.; Hauser, M.; Lindstrom, H. E. P.; Brown, A. G. A.; Ducourant, C.; Bossini, D.; Taylor, M. B.; Soubiran, C.; Hidalgo, S. L.; Sciacca, E.; Messineo, R.; Krone Martins, A.; Siltala, L.; Lanzafame, A. C.; Blanco Cuaresma, S.; Buzzi, R.; Turron, C.; Rohrbasser, L.; Bouquillon, S.; Aguado, J. J.; Robichon, N.; Plachy, E.; Lebzelter, T.; Barbato, D.; Montegriffo, P.; Bianchi, L.; David, M.; Walton, N. A.; Prsa, A.; Steele, I. A.; Pineau, F. X.; Pawlak, M.; Chaoul, Laurence; Fernández Hernández, J.; Vallenari, A.; Liao, S.; Fragkoudi, F.; Cánovas, H.; García Torres, M.; Smart, R. L.; Salgado, J.; González Núñez, J.; Noval, L.; Roelens, M.; De Luise, F.; Marconi, M.; Millar, N. R.; Re Fiorentin, P.; Cornez, T.; Ramos Lerate, M.; Blomme, R.; De Souza, R.; Jordi, C.; Souchay, J.; Thévenin, F.; Marshall, D. J.; Poujoulet, E.; Torra, J.; Galluccio, L.; De Angeli, F.; Crowley, C.; Marinoni, S.; Weiler, M.; Pourbaix, D.; De Laverny, P.; Fabre, C.; Arenou, F.; Diener, C.; Slezak, E.; Sanna, N.; Molnár, L.; Holland, G.; Szegedi Elek, E.; Drimmel, R.; Sánchez Giménez, V.; Pancino, E.; Fouron, C.; Álvarez, M. A.; Cioni, M. R. L.; Janßen, Katja; Zhao, H.; Pagano, I.; Chiavassa, A.; Geyer, R.; Panem, C.; Sartoretti, P.; Jevardat de Fombelle, G.; Abreu Aramburu, A.; Benson, K.; Rimoldini, L.; Orrù, G.; Frémat, Y.; Álvarez Cid Fuentes, J.; Casamiquela, L.; Mowlavi, N.; Castellani, M.; Gerlach, E.; Haywood, M.; Yvard, P.; Girona, S.; Di Matteo, P.; Wevers, T.; Tauran, G.; Rambaux, N.; Evans, D. W.; Ségransan, D.; Eyer, L.; Lasne, Y.; Torra, F.; Tanga, P.; Taris, F.; Süveges, M.; Karbevska, L.; Bragaglia, A.; Jordan, S.; Regibo, S.; Massari, D.; Hladczuk, N.; Nienartowicz, K.; Katz, D.; Brouillet, N.; Solano, Enrique; Yoldas, A.; Lebreton, Y.; Royer, F.; Schultheis, M.; Viala, Y.; Kordopatis, G.; Becciani, U.; Leccia, S.; Mora, A.; Roux, W.; Barache, C.; Sagristà Sellés, A.; Tonello, N.; Busso, G.; Bramante, S.; Abbas, U.; Sadowski, G.; García Lario, P.; Recio Blanco, A.; Le Fustec, Y.; Marcos Santos, M. M. S.; Roegiers, T.; Madrero Pardo, P.; Nicolas, C.; Castañeda, J.; Segovia, J. C.; Altmann, M.; Sozzetti, A.; Bakker, J.; Crifo, F.; Masip, A.; Di Stefano, E.; Hernández, J.; Carlucci, T.; Halbwachs, J. L.; Spoto, F.; Mignard, F.; Fabricius, C.; Riello, M.; Carnerero, M. I.; Del Pozo, E.; Baudesson Stella, A.; Dapergolas, A.; Souami, D.; Aerts, C.; Creevey, O. L.; Alves, J.; Juaristi Campillo, J.; Molinaro, R.; Ordénovic, C.; Haigron, R.; Morbidelli, R.; Livanou, E.; García Reinaldos, M.; Bellas Velidis, I.; Van Dillen, E.; Guiraud, J.; Marchal, O.; Racero, E.; Burgess, P. W.; Balog, Z.; Andrae, R.; Portell, J.; Penttilä, A.; Giuffrida, G.; Carrasco, J. M.; Samaras, N.; Pagani, C.; Anglada Varela, E.; Garofalo, A.; Granvik, M.; Pailler, F.; Gosset, E.; Raiteri, C. M.; Zorec, J.; Fouesneau, M.; Poggio, E.; Garabato, D.; Ramos, P.; Cooper, W. J.; Baker, S. G.; Fienga, A.; Zwitter, T.; Brugaletta, E.; Bertone, S.; Gómez, A.; Zurbach, C.; Breedt, E.; Babusiaux, C.; Rainer, M.; Rybicki, K. A.; David, P.; Robin, C.; Anderson, R. I.; Van Reeven, W.; Guerrier, A.; De Ridder, J.; Van Leeuwen, M.; Korn, A. J.; Salguero, E.; Lammers, U.; Cancelliere, R.; Huckle, H. E.; Busonero, D.; Sordo, R.; Pauwels, T.; Dafonte, C.; Jansen, F.; Licata, E.; Gai, M.; Lanza, A. F.; Riclet, F.; Delisle, J. B.; Lorca, A.; Dolding, C.; Peñalosa Esteller, X.; Solitro, F.; Burlacu, A.; Semeux, D.; Rixon, G.; Bressan, A.; Bauchet, N.; Damerdji, Y.; Helmi, A.; Charlot, P.; Bastian, U.; Fernique, P.; Bassilana, J. L.; Barros, M.; Szabados, L.; Morel, T.; Jasniewicz, G.; Van Leeuwen, F.; Spagna, A.; Enke, H.; Hodgkin, S. T.; Antoja, T.; Brucciarelli, B.; Vaillant, M.; Hambly, N. C.; Accart, S.; Teixeira, R.; Michalik, D.; Vanel, O.; Kontizas, M.; Faigler, S.; Heiter, U.; Bellazzini, M.; Gavras, P.; Morris, D.; Hatzidimitriou, D.; González Santamaría, I.; Löffler, W.; Unger, C.; Zucker, S.; Le Campion, J. F.; Eappachen, D.; De Torres, A.; Ajaj, M.; Klioner, S. A.; De Teodoro, P.; Poretti, E.; Lattanzi, M. G.; Osborne, Paul; Hilger, T.; Palicio, P. A.; Balaguer Núñez, L.; Crosta, M.; Lambert, S.; Moitinho, A.; Reylé, C.; Messina, S.; Randich, S.; Baines, D.; Lister, T. A.; Castro Sampol, P.; Bailer Jones, C. A. L.; Panuzzo, P.; Gutierrez Sánchez, R.; Jean Antonie Piccolo, A.; Cropper, M.; González Vidal, J. J.; Franke, F.; Bombrun, A.; Holl, B.; Kervella, P.; Martín Polo, L.; Fraile, E.; Figueras, F.; Teyssier, D.; Siddiqui, H. I.; Panahi, A.; Utrilla, E.; Seabroke, G. M.; Marchant, J. M.; Cantat Gaudin, T.; Hutton, A.; Cheek, N.; Butkevich, A. G.; Delgado, A.; Berthier, J.; Sarasso, M.; Davidson, M.; Plum, G.; Marocco, F.; Caffau, E.; Molina, D.; Siebert, A.; Prusti, T.; Mulone, A. F.; De Bruijne, J. H. J.; Cellino, A.; Harrison, D. L.; Ragaini, S.; Mann, R. G.; Forderung der wissenschaftlichen Forschung (FWF); Belgian federal Science Policy Office (BELSPO); Hertha Firnberg Programme; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Comite Francais d'Evaluation de la Cooperation Universitaire et Scientifique avec le Bresil (COFECUB); National Natural Science Foundation of China (NSFC); China Scholarship Council (CSC); European Commission (EC); European Research Council (ERC); Agence Nationale de la Recherche (ANR); European Space Agency (ESA); Centre National D'Etudes Spatiales (CNES); Istituto Nazionale di Astrofisica (INAF); Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR); Narodowe Centrum Nauki (NCN); Fundacao para a Ciencia e a Tecnologia (FCT); Slovenian Research Agency; Agencia Estatal de Investigación (AEI); Xunta de Galicia; Universitat de Barcelona (UB); Generalitat de Catalunya; Swedish National Space Agency (SNSA); United Kingdom Science and Technology Facilities Council (STFC); Krone Martins, A. [0000-0002-2308-6623]; Seabroke, G. [0000-0003-4072-9536]; Chiavassa, A. [0000-0003-3891-7554]; Castro Ginard, A. [0000-0002-9419-3725]; McMillan, P. [0000-0002-8861-2620]; Siltala, L. [0000-0002-6938-794X]; Delise, J. B. [0000-0001-5844-9888]; Aerts, C. [0000-0003-1822-7126]; Fedorets, G. [0000-0002-8418-4809]; Centro de Excelencia Científica Severo Ochoa, Instituto de Ciencias del Cosmos de la Universidad de Barcelona, SEV2015-0493; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2014-0369
Context. This work is part of the Gaia Data Processing and Analysis Consortium papers published with the Gaia Early Data Release 3 (EDR3). It is one of the demonstration papers aiming to highlight the improvements and quality of the newly published data by applying them to a scientific case. Aims. We use the Gaia EDR3 data to study the structure and kinematics of the Magellanic Clouds. The large distance to the Clouds is a challenge for the Gaia astrometry. The Clouds lie at the very limits of the usability of the Gaia data, which makes the Clouds an excellent case study for evaluating the quality and properties of the Gaia data. Methods. The basis of our work are two samples selected to provide a representation as clean as possible of the stars of the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC). The selection used criteria based on position, parallax, and proper motions to remove foreground contamination from the Milky Way, and allowed the separation of the stars of both Clouds. From these two samples we defined a series of subsamples based on cuts in the colour-magnitude diagram; these subsamples were used to select stars in a common evolutionary phase and can also be used as approximate proxies of a selection by age. Results. We compared the Gaia Data Release 2 and Gaia EDR3 performances in the study of the Magellanic Clouds and show the clear improvements in precision and accuracy in the new release. We also show that the systematics still present in the data make the determination of the 3D geometry of the LMC a difficult endeavour; this is at the very limit of the usefulness of the Gaia EDR3 astrometry, but it may become feasible with the use of additional external data. We derive radial and tangential velocity maps and global profiles for the LMC for the several subsamples we defined. To our knowledge, this is the first time that the two planar components of the ordered and random motions are derived for multiple stellar evolutionary phases in a galactic disc outside the Milky Way, showing the differences between younger and older phases. We also analyse the spatial structure and motions in the central region, the bar, and the disc, providing new insightsinto features and kinematics. Finally, we show that the Gaia EDR3 data allows clearly resolving the Magellanic Bridge, and we trace the density and velocity flow of the stars from the SMC towards the LMC not only globally, but also separately for young and evolved populations. This allows us to confirm an evolved population in the Bridge that is slightly shift from the younger population. Additionally, we were able to study the outskirts of both Magellanic Clouds, in which we detected some well-known features and indications of new ones.
Acceso Abierto
Gaia Early Data Release 3 The Galactic anticentre
(EDP Sciences, 2021-04-28) Antoja, T.; McMillan, P. J.; Kordopatis, G.; Ramos, P.; Helmi, A.; Balbinot, E.; Cantat Gaudin, T.; Chemin, L.; Figueras, F.; Jordi, C.; Khanna, S.; Marchal, O.; Pineau, F. X.; Taris, F.; Fabricius, C.; Salgado, J.; Pawlak, M.; Davidson, M.; Lobel, A.; Anglada Varela, E.; Rowell, N.; Evans, D. W.; Marinoni, S.; Busonero, D.; Ripepi, V.; Segovia, J. C.; Burlacu, A.; Randich, S.; Hodgkin, S. T.; Fabrizio, M.; Sciacca, E.; Hambly, N. C.; Kochoska, A.; Regibo, S.; Franke, F.; García Lario, P.; Lasne, Y.; Messineo, R.; Robin, C.; Anderson, R. I.; Kontizas, M.; Fienga, A.; Lecoeur Taibi, I.; Palicio, P. A.; Roelens, M.; Walton, N. A.; Garabato, D.; Fedorets, G.; Recio Blanco, A.; Jansen, F.; Le Fustec, Y.; Kostrzewa Rutkowska, Z.; Muraveva, T.; Hidalgo, S. L.; Montegriffo, P.; Gilmore, G.; García Gutierrez, A.; Baines, D.; Baker, S. G.; Balaguer Núñez, L.; Balog, Z.; Barbato, D.; Bauchet, N.; Bertone, S.; Siebert, A.; González Vidal, J. J.; Breedt, E.; Steele, I. A.; Jasniewicz, G.; Tauron, C.; Osborne, Paul; Carlucci, T.; Brown, A. G. A.; Korn, A. J.; Biermann, M.; Busso, G.; Jonker, P. G.; Ducourant, C.; Sarro, L. M.; Altavilla, G.; Sanna, V.; Delgado, A.; Crifo, F.; Kervella, P.; Fernández Hernández, J.; Spoto, F.; Katz, D.; Drimmel, R.; Harrison, D. L.; Aerts, C.; Segol, M.; De Torres, A.; Bakker, J.; Geyer, R.; Masana, E.; Andrae, R.; Klioner, S. A.; Diener, C.; Marchant, J. M.; Seabroke, G. M.; Creevey, O. L.; Viala, Y.; Mora, A.; Abbas, U.; Slezak, E.; Teixeira, R.; De Luise, F.; Bailer Jones, C. A. L.; Enke, H.; Pailler, F.; Royer, F.; Gutiérrez Sánchez, R.; Guiraud, J.; Brugaletta, E.; Granvik, M.; Richards, P. J.; Carballo, R.; Bassilana, J. L.; Weiler, M.; Butkevich, A. G.; Marcos Santos, M. M. S.; Messina, S.; Babusiaux, C.; Pulone, L.; Vallenari, A.; Mowlavi, N.; Eappachen, D.; Plachy, E.; Massari, D.; Ramos Lerate, M.; Nicolas, C.; Hutton, A.; Ordénovic, C.; Martín Fleitas, J. M.; Crosta, M.; Sartoretti, P.; Arenou, F.; Poggio, E.; Lattanzi, M. G.; Orrù, G.; Morbidelli, R.; Mints, A.; Rambaux, N.; Prsa, A.; Giacobbe, P.; De Bruijne, J. H. J.; Fernique, P.; Fraile, E.; García Torres, M.; Cellino, A.; Giuffrida, G.; Garía Reinaldos, M.; Soubiran, C.; Siopis, C.; Cornez, T.; Hladczuk, N.; Jevardat de Fombelle, G.; Plum, G.; Cheek, N.; Hauser, M.; Van Reeven, W.; De Laverny, P.; Diakite, S.; Altmann, M.; Lister, T. A.; González Núñez, J.; Piersimoni, A. M.; Bramante, L.; Abreu Aramburu, A.; Smith, M.; Blanco Cuaresma, S.; Delgado, H. E.; Blomme, R.; Liao, S.; Jordan, S.; Mor, R.; Álvarez, M. A.; Bartolomé, S.; Lorca, A.; Mann, R. G.; Janßen, Katja; Manteiga, M.; Halbwachs, J. L.; Brouillet, N.; Del Peloso, E. F.; Clementini, G.; Haigron, R.; Lebzelter, T.; Roegiers, T.; Marconi, M.; Panuzzo, P.; Musella, I.; Ajaj, M.; Salguero, E.; Mazeh, T.; Crowley, C.; Lindstrom, H. E. P.; Fragkoudi, F.; Heiter, U.; Lammers, U.; Delisle, J. B.; Van Leeuwen, F.; Berthier, J.; Castañeda, J.; Álvarez Cid Fuentes, J.; Marrese, P. M.; Vicente, D.; Pourbaix, D.; Fouesneau, M.; Alves, J.; Solitro, F.; Cowell, S.; Mignard, F.; Riello, M.; Robin, A. C.; Zucker, S.; Sozzetti, A.; Utrilla, E.; Ségransan, D.; Sarasso, M.; Marocco, F.; Marshall, D. J.; Martín Polo, L.; Masip, A.; Kruszynska, K.; Molina, D.; Bianchi, L.; Morris, D.; Souami, D.; Tauran, G.; Molinero, R.; Pagani, C.; Carrasco, J. M.; Prusti, T.; Chaoul, Laurence; Lanzafame, A. C.; De March, R.; Lebreton, Y.; Managau, S.; Barstow, M. A.; Poretti, E.; Unger, N.; Girona, S.; Del Pozo, E.; Charlot, P.; Gavras, P.; Livanou, E.; Becciani, U.; Re Fiorentin, P.; De Teodoro, P.; Bressan, A.; Panahi, A.; Comoretto, G.; Hilger, T.; Carnerero, M. I.; Rimoldini, L.; Buzzi, R.; González Santamaría, I.; Licata, E.; Boch, T.; Rainer, M.; David, M.; Rohrbasser, L.; Audard, Marc; Solano, Enrique; Di Matteo, P.; Gracia Abril, G.; Smart, R. L.; Lambert, S.; Creylé, C.; Cancelliere, R.; Murphy, C. P.; Teyssier, D.; Ulla, A.; Baudesson Stella, A.; Casamiquela, L.; Distefano, E.; Chiavassa, A.; Haztdimitriou, D.; Thévenin, F.; Dolding, C.; Delchambre, L.; Rybizki, J.; Pancino, E.; Dafonte, C.; Dapergolas, A.; Hernández, J.; De Ridder, J.; Caffau, E.; Faigler, S.; Rybicki, K. A.; Sadowski, G.; Sagristà Sellés, A.; Sahlmann, J.; Samaras, N.; Schultheis, M.; Garofalo, A.; Siddiqui, H. I.; Dell´Oro, A.; Gosset, E.; Spagna, A.; Holland, G.; Krone Martins, A.; Juaristi Campillo, J.; Castro Ginard, A.; Romero Gómez, M.; Ragaini, S.; Robichon, N.; Fouron, C.; Zurbach, C.; Morel, T.; Löffler, W.; Leccia, S.; Molnár, L.; Riva, A.; Gai, M.; Frémat, Y.; Panem, C.; Gómez, A.; Moitinho, A.; Osinde, J.; Hobbs, D.; Julbe, F.; Guy, L. P.; Muñoz, D.; Michalik, D.; Gerlach, E.; De Angeli, F.; Le Campion, J. F.; Nienartowicz, K.; Van Leeuwen, M.; Madrero Pardo, P.; Millar, N. R.; Damerdji, Y.; Pojoulet, E.; Guerrier, A.; Haywood, M.; Cooper, W. J.; Barros, M.; De Souza, R.; Huckle, H. E.; Burgess, P. W.; Karbevska, L.; Bellazzini, M.; Barache, C.; Bellas Velidis, I.; Bouquillon, S.; David, P.; Fabre, C.; Lanza, A. F.; Cánovas, H.; Leclerc, N.; Bagaglia, A.; Bernet, M.; Riclet, F.; Roux, W.; Sordo, R.; Tanga, P.; Portell, J.; Benson, K.; Carry, B.; Mulone, A. F.; Bucciarelli, B.; Galluccio, L.; Palaversa, L.; Castellani, M.; Peñalosa Esteller, X.; Luri, X.; Holl, B.; Muinonen, K.; Mastrobuono Battisti, A.; Destroffer, D.; Semeux, D.; Castro Sampol, P.; Raiteri, C. M.; Cropper, M.; Jean Antonie Piccolo, A.; Esquej, P.; Eyer, L.; Pauwels, T.; Cioni, M. R. L.; Souchay, J.; Pagano, I.; Penttilä, A.; Noval, L.; Siltala, L.; Guerra, R.; Bastian, U.; Accart, S.; Racero, E.; Bossini, D.; Rixon, G.; Santoveña, R.; Bombrun, A.; Zwitter, T.; Aguado, J. J.; Sánchez Giménez, V.; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MINECO/ICTI2013-2016/MDM-2014-0369; Centrode Excelencia Científica Instituto de Ciencias del Cosmos Universidad de Barcelona, MINECO/ICTI2013-2016/SEV2015-0493; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); National Natural Science Foundation of China (NSFC); Estonian Ministry of Education and Research; Centre National D'Etudes Spatiales (CNES); Agence Nationale de la Recherche (ANR); Centre National de la Recherche Scientifique (CNRS); European Commission (EC); European Research Council (ERC); Institut des Sciences de l'Univers (INSU); Institut National Polytechnique (INP); Institut National de Physique nucleaire et de Physique des Particules (IN2P3); Deutsches Zentrum für Luft- und Raumfahrt (DLR); Hungarian Academy of Sciences; Hungarian National Research, Development, and Innovation Office (NKFIH); Science Foundation Ireland (SFI); Israel Science Foundation (ISF); Agenzia Spaziale Italiana (ASI); Italian Istituto Nazionale di Astrofisica (INAF); Netherlands Organisation for Scientific Research (NWO); Polish National Science Centre; Ministry of Science and Higher Education (MNiSW); Fundacao para a Ciencia e a Tecnologia (FCT); Slovenian Research Agency; Xunta de Galicia; Agencia Estatal de Investigación (AEI); Generalitat de Catalunya; United Kingdom Science and Technology Facilities Council (STFC); United Kingdom Space Agency (UKSA); Krone Martins, A. [0000-0002-2308-6623]; McMillan, P. [0000-0002-8861-2620]; Carrasco Martínez, J. P. [0000-0002-3029-5853]; Sozzetti, A. [0000-0002-7504-365X]; Centros de Excelencia Severo Ochoa, BARCELONA SUPERCOMPUTING CENTER (BSC), SEV2015-0493
Aims. We aim to demonstrate the scientific potential of the Gaia Early Data Release 3 (EDR3) for the study of different aspects of the Milky Way structure and evolution and we provide, at the same time, a description of several practical aspects of the data and examples of their usage. Methods. We used astrometric positions, proper motions, parallaxes, and photometry from EDR3 to select different populations and components and to calculate the distances and velocities in the direction of the anticentre. In this direction, the Gaia astrometric data alone enable the calculation of the vertical and azimuthal velocities; also, the extinction is relatively low compared to other directions in the Galactic plane. We then explore the disturbances of the current disc, the spatial and kinematical distributions of early accreted versus in situ stars, the structures in the outer parts of the disc, and the orbits of open clusters Berkeley 29 and Saurer 1. Results. With the improved astrometry and photometry of EDR3, we find that: (i) the dynamics of the Galactic disc are very complex with oscillations in the median rotation and vertical velocities as a function of radius, vertical asymmetries, and new correlations, including a bimodality with disc stars with large angular momentum moving vertically upwards from below the plane, and disc stars with slightly lower angular momentum moving preferentially downwards; (ii) we resolve the kinematic substructure (diagonal ridges) in the outer parts of the disc for the first time; (iii) the red sequence that has been associated with the proto-Galactic disc that was present at the time of the merger with Gaia-Enceladus-Sausage is currently radially concentrated up to around 14 kpc, while the blue sequence that has been associated with debris of the satellite extends beyond that; (iv) there are density structures in the outer disc, both above and below the plane, most probably related to Monoceros, the Anticentre Stream, and TriAnd, for which the Gaia data allow an exhaustive selection of candidate member stars and dynamical study; and (v) the open clusters Berkeley 29 and Saurer 1, despite being located at large distances from the Galactic centre, are on nearly circular disc-like orbits. Conclusions. Even with our simple preliminary exploration of the Gaia EDR3, we demonstrate how, once again, these data from the European Space Agency are crucial for our understanding of the different pieces of our Galaxy and their connection to its global structure and history.
Acceso Abierto
Gliese 49: activity evolution and detection of a super-Earth A HADES and CARMENES collaboration
(EDP Sciences, 2019-04-24) Perger, M.; Scandariato, G.; Ribas, I.; Morales, J. C.; Affer, L.; Azzaro, M.; Amado, P. J.; Anglada Escudé, G.; Baroch, D.; Barrado, D.; Bauer, F. F.; Béjar, V. J. S.; Caballero, J. A.; Cortés Contreras, M.; Damasso, M.; Dreizler, S.; González Cuesta, L.; González Hernández, J. I.; Guenther, E. W.; Henning, T.; Herrero, Enrique; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Leto, G.; López González, M. J.; Maldonado, J.; Micela, G.; Montes, D.; Pinamonti, M.; Quirrenbach, A.; Rebolo, R.; Reiners, A.; Rodríguez, E.; Rodríguez López, C.; Schimitt, J. H. M. M.; Sozzetti, A.; Suárez Mascareño, A.; Toledo Padrón, B.; Zanmar Sánchez, R.; Zapatero Osorio, M. R.; Zechmeister, M.; Ministerio de Economía y Competitividad (MINECO); European Commission (EC); Agencia Estatal de Investigación (AEI); 0000-0001-7098-0372; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. Small planets around low-mass stars often show orbital periods in a range that corresponds to the temperate zones of their host stars which are therefore of prime interest for planet searches. Surface phenomena such as spots and faculae create periodic signals in radial velocities and in observational activity tracers in the same range, so they can mimic or hide true planetary signals. Aims. We aim to detect Doppler signals corresponding to planetary companions, determine their most probable orbital configurations, and understand the stellar activity and its impact on different datasets. Methods. We analyzed 22 yr of data of the M1.5 V-type star Gl 49 (BD+61 195) including HARPS-N and CARMENES spectrographs, complemented by APT2 and SNO photometry. Activity indices are calculated from the observed spectra, and all datasets are analyzed with periodograms and noise models. We investigated how the variation of stellar activity imprints on our datasets. We further tested the origin of the signals and investigate phase shifts between the different sets. To search for the best-fit model we maximize the likelihood function in a Markov chain Monte Carlo approach. Results. As a result of this study, we are able to detect the super-Earth Gl 49b with a minimum mass of 5.6 M⊕. It orbits its host star with a period of 13.85 d at a semi-major axis of 0.090 au and we calculate an equilibrium temperature of 350 K and a transit probability of 2.0%. The contribution from the spot-dominated host star to the different datasets is complex, and includes signals from the stellar rotation at 18.86 d, evolutionary timescales of activity phenomena at 40–80 d, and a long-term variation of at least four years.
Acceso Abierto
HADES RV Programme with HARPS-N at TNG XIII. A sub-Neptune around the M dwarf GJ 720 A
(EDP Sciences, 2021-05-31) González Álvarez, E.; Petralia, A.; Micela, G.; Maldonado, J.; Affer, L.; Maggio, A.; Covino, E.; Damasso, M.; Lanza, A. F.; Perger, M.; Pinamonti, M.; Poretti, E.; Scandariato, G.; Sozzetti, A.; Bignamini, A.; Giacobbe, P.; Leto, G.; Pagano, I.; Zanmar Sánchez, R.; González Hernández, J. I.; Rebolo, R.; Ribas, I.; Suárez Mascareño, A.; Toledo Padrón, B.; National Science Foundation (USA NSF); Agenzia Spaziale Italiana (ASI); Generalitat de Catalunya; Fundación Caixa; Agencia Estatal de Investigación (AEI); González Álvarez, E. [0000-0002-4820-2053]; Petralia, A. [0000-0002-9882-1020]; Maldonado, J. [0000-0002-2218-5689]; Affer, L. [0000-0001-5600-3778]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The high number of super-Earth and Earth-like planets in the habitable zone detected around M-dwarf stars in recent years has revealed these stellar objects to be the key to planetary radial velocity (RV) searches. Aims. Using the HARPS-N spectrograph within The HArps-n red Dwarf Exoplanet Survey (HADES) we have reached the precision needed to detect small planets with a few Earth masses using the spectroscopic radial velocity technique. HADES is mainly focused on the M-dwarf population of the northern hemisphere. Methods. We obtained 138 HARPS-N RV measurements between 2013 May and 2020 September of GJ 720 A, classified as an M0.5 V star located at a distance of 15.56 pc. To characterize the stellar variability and to distinguish the periodic variation due to the Keplerian signals from those related to stellar activity, the HARPS-N spectroscopic activity indicators and the simultaneous photometric observations with the APACHE and EXORAP transit surveys were analyzed. We also took advantage of TESS, MEarth, and SuperWASP photometric surveys. The combined analysis of HARPS-N RVs and activity indicators let us address the nature of the periodic signals. The final model and the orbital planetary parameters were obtained by simultaneously fitting the stellar variability and the Keplerian signal using a Gaussian process regression and following a Bayesian criterion. Results. The HARPS-N RV periodic signals around 40 days and 100 days have counterparts at the same frequencies in HARPS-N activity indicators and photometric light curves. We thus attribute these periodicities to stellar activity; the first period is likely associated with the stellar rotation. GJ 720 A shows the most significant signal at 19.466 ± 0.005 days with no counterparts in any stellar activity indices. We hence ascribe this RV signal, having a semi-amplitude of 4.72 ± 0.27 m s−1, to the presence of a sub-Neptune mass planet. The planet GJ 720 Ab has a minimum mass of 13.64 ± 0.79 M⊕, it is in circular orbit at 0.119 ± 0.002 AU from its parent star, and lies inside the inner boundary of the habitable zone around its parent star.
Acceso Abierto
HADES RV programme with HARPS-N at TNG XIV. A candidate super-Earth orbiting the M-dwarf GJ 9689 with a period close to half the stellar rotation period
(EDP Sciences, 2021-07-12) Maldonado, J.; Petralia, A.; Damasso, M.; Pinamonti, M.; Scandariato, G.; González Álvarez, E.; Affer, L.; Micela, G.; Lanza, A. F.; Leto, G.; Poretti, E.; Sozzetti, A.; Perger, M.; Giacobbe, P.; Zanmar Sánchez, R.; Maggio, A.; González Hernández, J. I.; Rebolo, R.; Ribas, I.; Suárez Mascareño, A.; Toledo Padrón, B.; Bignamini, A.; Molinari, E.; Covino, E.; Claudi, R.; Desidera, S.; Herrero, Enrique; Morales, J. C.; Pagano, I.; Piotto, G.; Agencia Estatal de Investigación (AEI); Generalitat de Catalunya; Maldonado, J. [0000-0002-2218-5689]; Petralia, A. [0000-0002-9882-1020]; Damasso, M. [0000-0001-9984-4278]; Pinamonti, M. [0000-0002-4445-1845]; Affer, L. [0000-0001-5600-3778]; Lanza, A. F. [0000-0001-5928-7251]; Leto, G. [0000-0002-0040-5011]; Poretti, E. [0000-0003-1200-0473]; Sozzetti, A. [0000-0002-7504-365X]; Perger, M. [0000-0001-7098-0372]; Zanmar Sánchez, R. [0000-0002-6997-0887]; Maggio, A. [0000-0001-5154-6108]; González Hernández, J. I. [0000-0002-0264-7356]; Ribas, I. [0000-0002-6689-0312]; Toledo Padrón, B. [0000-0002-8194-215X]; Bignamini, A. [0000-0002-5606-6354]; Molinari, E. [0000-0002-1742-7735]; Covino, E. [0000-0002-7579-2298]; Claudi, R. [0000-0001-7707-5105]; Desidera, S. [0000-0001-8613-2589]
Context. It is now well-established that small, rocky planets are common around low-mass stars. However, the detection of such planets is challenged by the short-term activity of host stars. Aims. The HARPS-N red Dwarf Exoplanet Survey programme is a long-term project at the Telescopio Nazionale Galileo aimed at monitoring nearby, early-type, M dwarfs, using the HARPS-N spectrograph to search for small, rocky planets. Methods. A total of 174 HARPS-N spectroscopic observations of the M0.5V-type star GJ 9689 taken over the past seven years have been analysed. We combined these data with photometric measurements to disentangle signals related to the stellar activity of the star from possible Keplerian signals in the radial velocity data. We ran an MCMC analysis, applying Gaussian process regression techniques to model the signals present in the data. Results. We identify two periodic signals in the radial velocity time series, with periods of 18.27 and 39.31 d. The analysis of the activity indexes, photometric data, and wavelength dependency of the signals reveals that the 39.31 d signal corresponds to the stellar rotation period. On the other hand, the 18.27 d signal shows no relation to any activity proxy or the first harmonic of the rotation period. We, therefore, identify it as a genuine Keplerian signal. The best-fit model describing the newly found planet, GJ 9689 b, corresponds to an orbital period of Pb = 18.27 ± 0.01 d and a minimum mass of MP sini = 9.65 ± 1.41 M⊕.
Acceso Abierto
K2-111: an old system with two planets in near-resonance.
(Oxford Academics: Blackwell Publishing, 2020-10-27) Mortier, A.; Zapatero Osorio, M. R.; Malavolta, L.; Alibert, Y.; Rice, K.; Lillo Box, J.; Vanderburg, A.; Oshagh, M.; Buchhave, L. A.; Adibekyan, V.; Delgado Mena, E.; López Morales, M.; Charbonneau, D.; Sousa, S. G.; Lovis, C.; After, L.; Allende Prieto, C.; Barros, S. C. C.; Benatti, S.; Bonomo, A. S.; Boschin, W.; Bouchy, F.; Cabral, A.; Collier Cameron, A.; Cosentino, R.; Cristiani, S.; Demangeon, O. D. S.; Di Marcantonio, P.; D´Odorico, V.; Dumusque, X.; Ehrenreich, D.; Figueira, P.; Fiorenzano, A. F. M.; Ghedina, A.; González Hernández, J. I.; Haldemann, J.; Harutyunyan, A.; Haywood, R. D.; Latham, D. W.; Lavie, B.; Lo Curto, G.; Maldonado, J.; Menescau, A.; Martins, C. J. A. P.; Mayor, M.; Mégevand, D.; Mehner, A.; Micela, G.; Molaro, P.; Molinari, E.; Nunes, Nelson J.; Pepe, Francesco; Pallé, E.; Phillips, D.; Piotto, G.; Pinamonti, M.; Poretti, E.; Rivas, M.; Rebolo, R.; Santos, Nuno C.; Sasselov, D.; Sozzetti, A.; Suárez Mascareño, A.; Udry, S.; West, R. G.; Watson, C. A.; Wilson, T. G.; Science and Technology Facilities Council (STFC); Istituto Nazionale di Astrofisica (INAF); Swiss National Science Foundation (SNSF); Fundação para a Ciência e a Tecnologia (FCT); National Aeronautics and Space Administration (NASA); European Research Council (ERC); 0000-0002-9433-871X; 0000-0002-3814-5323; 0000-0002-0571-4163; 0000-0003-4434-2195; 0000-0003-1605-5666; 0000-0001-7246-5438; 0000-0003-2434-3625; 0000-0003-1231-2389; 0000-0003-1784-1431; 0000-0002-7504-365X; 0000-0002-0601-6199; 0000-0001-8749-1962; 0000-0002-8863-7828; 0000-0003-4422-2919; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
This paper reports on the detailed characterization of the K2-111 planetary system with K2, WASP, and ASAS-SN photometry, as well as high-resolution spectroscopic data from HARPS-N and ESPRESSO. The host, K2-111, is confirmed to be a mildly evolved (log g = 4.17), iron-poor ([Fe/H]=-0.46), but alpha-enhanced ([alpha/Fe]=0.27), chromospherically quiet, very old thick disc G2 star. A global fit, performed by using PyORBIT, shows that the transiting planet, K2-111 b, orbits with a period P-b = 5.3518 +/- 0.0004 d and has a planet radius of 1.82(-0.09)(+0.11) R-circle plus and a mass of 5.29(-0.77)(+0.76) M-circle plus, resulting in a bulk density slightly lower than that of the Earth. The stellar chemical composition and the planet properties are consistent with K2-111 b being a terrestrial planet with an iron core mass fraction lower than the Earth. We announce the existence of a second signal in the radial velocity data that we attribute to a non-transiting planet, K2-111 c, with an orbital period of 15.6785 +/- 0.0064 d, orbiting in near-3:1 mean motion resonance with the transiting planet, and a minimum planet mass of 11.3 +/- 1.1M(circle plus). Both planet signals are independently detected in the HARPS-N and ESPRESSO data when fitted separately. There are potentially more planets in this resonant system, but more well-sampled data are required to confirm their presence and physical parameters.
Restringido
Nightside condensation of iron in an ultrahot giant exoplanet
(Nature Research Journals, 2020-03-11) Ehrenreich, D.; Lovis, C.; Allart, R.; Zapatero Osorio, M. R.; Pepe, Francesco; Cristiani, S.; Rebolo, R.; Santos, Nuno C.; Borsa, F.; Demangeon, O. D. S.; Dumusque, X.; González Hernández, J. I.; Casasayas Barris, N.; Séngrasan, D.; Sousa, S. G.; Abreu, M.; Adibekyan, V.; Affolter, M.; Allende Prieto, C.; Alibert, Y.; Aliverti, M.; Alves, D.; Amate, M.; Ávila, G.; Baldini, V.; Bandy, T.; Benz, W.; Bianco, A.; Bolmont, É.; Bouchy, F.; Bourrier, V.; Broeg, C.; Cabral, A.; Calderone, G.; Pallé, E.; Cegla, H. M.; Cirami, R.; Coelho, João M. P.; Conconi, P.; Coretti, I.; Cumani, C.; Cupani, G.; Dekker, H.; Delabre, B.; Deiries, S.; D´Odorico, V.; Di Marcantonio, P.; Figueira, P.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; Harada, N.; Hughes, I.; Iwert, O.; Kerber, F.; Knudstrup, J.; Landoni, M.; Lavie, B.; Lizon, Jean Louis; Lendl, M.; Lo Curto, G.; Maire, C.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Micela, G.; Modigliani, A.; Molaro, P.; Monteiro, M.; Monteiro, M. A.; Moschetti, M.; Muller, N.; Nunes, Nelson J.; Oggioni, L.; Oliveira, António; Pariani, G.; Pasquini, L.; Poretti, E.; Rasilla, J. L.; Redaelli, E.; Riva, M.; Santana Tschudi, S.; Santin, P.; Santos, Pedro; Segovia Milla, A.; Seidel, J. V.; Sosnowska, D.; Sozzetti, A.; Spanò, P.; Suárez Mascareño, A.; Tabernero, H. M.; Tenegi, F.; Udry, S.; Zanutta, A.; Zerbi, Filippo M.; European Research Council (ERC); Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Suárez Mascareño, A. [0000-0002-3814-5323]; Abreu, M. [0000-0002-0716-9568]; João M. P. Coelho. [0000-0002-4339-0550]; Monteiro, M. J. [0000-0003-0513-8116]; Tabernero, H. [0000-0002-8087-4298]; Nunes, N. J. [0000-0002-3837-6914]; Cabral, A. [0000-0002-9433-871X]; Molaro, P. [0000-0002-0571-4163]; Redaelli, E. M. A. [0000-0001-8185-2122]; Zapatero Osorio, M. R. [0000-0001-5664-2852]; Castro Alves, D. [0000-0001-7026-2514]; Seidel, J. V. [0000-0002-7990-9596]; Martins, C. J. A. P. [0000-0002-4886-9261]; Adibekyan, V. [0000-0002-0601-6199]; Zerbi, F. M. [0000-0002-9996-973X]; Monteiro, M. [0000-0001-5644-0898]; Mehner, A. [0000-0002-9564-3302]; Santos, N. [0000-0003-4422-2919]; Cegla, H. [0000-0001-8934-7315]; Sozzetti, A. [0000-0002-7504-365X]; Allart, R. [0000-0002-1199-9759]; Landoni, M. [0000-0001-5570-5081]; Coretti, I. [0000-0001-9374-3249]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Ultrahot giant exoplanets receive thousands of times Earth’s insolation1,2. Their high-temperature atmospheres (greater than 2,000 kelvin) are ideal laboratories for studying extreme planetary climates and chemistry3,4,5. Daysides are predicted to be cloud-free, dominated by atomic species6 and much hotter than nightsides5,7,8. Atoms are expected to recombine into molecules over the nightside9, resulting in different day and night chemistries. Although metallic elements and a large temperature contrast have been observed10,11,12,13,14, no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night (‘evening’) and night-to-day (‘morning’) terminators could, however, be revealed as an asymmetric absorption signature during transit4,7,15. Here we report the detection of an asymmetric atmospheric signature in the ultrahot exoplanet WASP-76b. We spectrally and temporally resolve this signature using a combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by −11 ± 0.7 kilometres per second on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside16. In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. We conclude that iron must therefore condense during its journey across the nightside.
Acceso Abierto
Revisiting Proxima with ESPRESSO
(EDP Sciences, 2020-07-13) Suárez Mascareño, A.; Faria, J. P.; Figueira, P.; Lovis, C.; Damasso, M.; González Hernández, J. I.; Rebolo, R.; Cristiani, S.; Pepe, Francesco; Santos, Nuno C.; Zapatero Osorio, M. R.; Adibekyan, V.; Hojjatpanah, S.; Sozzetti, A.; Murgas Alcaino, F.; Abreu, M.; Affolter, M.; Alibert, Y.; Aliverti, M.; Allart, R.; Allende Prieto, C.; Alves, D.; Amate, M.; Ávila, G.; Baldini, V.; Bandi, T.; Barros, S. C. C.; Bianco, A.; Benz, W.; Bouchy, F.; Broeg, C.; Cabral, A.; Calderone, G.; Cirami, R.; Coelho, J.; Conconi, P.; Coretti, I.; Cumani, C.; Cupani, G.; D´Odorico, V.; Deiries, S.; Delabre, B.; Di Marcantonio, P.; Dumusque, X.; Ehrenreich, D.; Fragoso, A.; Genolet, L.; Genoni, M.; Génova Santos, R.; Hughes, I.; Iwert, O.; Kerber, F.; Knudstrup, J.; Landoni, M.; Lavie, B.; Lillo Box, J.; Lizon, Jean Louis; Lo Curto, G.; Maire, C.; Manescau, A.; Martins, C. J. A. P.; Mégevand, D.; Mehner, A.; Micela, G.; Modigliani, A.; Molaro, P.; Monteiro, M. A.; Monteiro, M. J. P. F. G.; Moschetti, M.; Mueller, E.; Nunes, Nelson J.; Oggioni, L.; Oliveira, António; Pallé, E.; Pariani, G.; Pasquini, L.; Poretti, E.; Rasilla, J. L.; Redaelli, E.; Riva, M.; Santana Tschudi, S.; Santin, P.; Santos, Pedro; Segovia, A.; Sosnowska, D.; Sousa, S. G.; Spanò, P.; Tenegi, F.; Udry, S.; Zanutta, A.; Zerbi, Filippo M.; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); European Research Council (ERC); Lillo Box, J. [0000-0003-3742-1987]; Faria, J. [0000-0002-6728-244X]; Nunes, N. J. [0000-0002-3837-6914]; Molaro, P. [0000-0002-0571-4163]; Mascareño, A. S. [0000-0002-3814-5323]; Cabral, A. [0000-0002-9433-871X]; Monteiro, M. J. P. F. G. [0000-0003-0513-8116]; Redaelli, E. M. A. [0000-0001-8185-2122]; Barros, S. [0000-0003-2434-3625]; Santos, N. [0000-0003-4422-2919]; Abreu, M. [0000-0002-0716-9568]; Coretti, I. [0000-0001-9374-3249]; Sozzetti, A. [0000-0002-7504-365X]; Adibekyan, V. [0000-0002-0601-6199]; Monteiro, M. [0000-0001-5644-0898]; Damasso, M. [0000-0001-9984-4278]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The discovery of Proxima b marked one of the most important milestones in exoplanetary science in recent years. Yet the limited precision of the available radial velocity data and the difficulty in modelling the stellar activity calls for a confirmation of the Earth-mass planet. Aims. We aim to confirm the presence of Proxima b using independent measurements obtained with the new ESPRESSO spectrograph, and refine the planetary parameters taking advantage of its improved precision. Methods. We analysed 63 spectroscopic ESPRESSO observations of Proxima (Gl 551) taken during 2019. We obtained radial velocity measurements with a typical radial velocity photon noise of 26 cm s−1. We combined these data with archival spectroscopic observations and newly obtained photometric measurements to model the stellar activity signals and disentangle them from planetary signals in the radial velocity (RV) data. We ran a joint Markov chain Monte Carlo analysis on the time series of the RV and full width half maximum of the cross-correlation function to model the planetary and stellar signals present in the data, applying Gaussian process regression to deal with the stellar activity signals. Results. We confirm the presence of Proxima b independently in the ESPRESSO data and in the combined ESPRESSO+ HARPS+UVES dataset. The ESPRESSO data on its own shows Proxima b at a period of 11.218 ± 0.029 days, with a minimum mass of 1.29 ± 0.13 M⊕. In the combined dataset we measure a period of 11.18427 ± 0.00070 days with a minimum mass of 1.173 ± 0.086 M⊕. We get a clear measurement of the stellar rotation period (87 ± 12 d) and its induced RV signal, but no evidence of stellar activity as a potential cause for the 11.2 days signal. We find some evidence for the presence of a second short-period signal, at 5.15 days with a semi-amplitude of only 40 cm s−1. If caused by a planetary companion, it would correspond to a minimum mass of 0.29 ± 0.08 M⊕. We find that forthe case of Proxima, the full width half maximum of the cross-correlation function can be used as a proxy for the brightness changes and that its gradient with time can be used to successfully detrend the RV data from part of the influence of stellar activity. The activity-induced RV signal in the ESPRESSO data shows a trend in amplitude towards redder wavelengths. Velocities measured using the red end of the spectrograph are less affected by activity, suggesting that the stellar activity is spot dominated. This could be used to create differential RVs that are activity dominated and can be used to disentangle activity-induced and planetary-induced signals. The data collected excludes the presence of extra companions with masses above 0.6 M⊕ at periods shorter than 50 days.