Examinando por Autor "Delgado Mena, E."

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Acceso Abierto
A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113
(Oxford Academics: Oxford University Press, 2021-01-25) Osborn, Hugh P.; Armstrong, D. J.; Adibekyan, V.; Collins, K. A.; Delgado Mena, E.; Howell, Steve B.; Hellier, C.; King, G. W.; Lillo Box, J.; Nielsen, L. D.; Otegi, Jon F.; Santos, Nuno C.; Ziegler, C.; Anderson, D. R.; Briceño, C.; Burke, C. J.; Bayliss, D.; Barrado, D.; Bryant, E. M.; Brown, D. J. A.; Barros, S. C. C.; Bouchy, F.; Caldwell, D. A.; Conti, D.; Díaz, R. F.; Dragomir, D.; Deleuil, M.; Demangeon, O. D. S.; Dorn, C.; Daylan, T.; Figueira, P.; Helled, R.; Hoyer, S.; Jenkins, J. S.; Jensen, E. L. N.; Latham, D. W.; Law, N.; Louie, D.; Mann, A. W.; Osborn, A.; Pollacco, D.; Rodríguez, D. R.; Rackham, B. V.; Ricker, George; Scott, N. J.; Sousa, S. G.; Seager, S.; Stassun, K. G.; Smith, J. C.; Strom, P.; Udry, S.; Villaseñor, J. N.; Vanderspek, R.; West, R.; Wheatley, Peter; Winn, J. N.; Fundacao para a Ciencia e a Tecnologia (FCT); Science and Technology Facilities Council (STFC); Agencia Estatal de Investigación (AEI); National Aeronautics and Space Administration (NASA); UK Space Agency; Dorn, C. [0000-0001-6110-4610]; Anderson, D. [0000-0001-7416-7522]; Barros, S. [0000-0003-2434-3625]; Adibekyan, V. [0000-0002-0601-6199]; Armstrong, D. [0000-0002-5080-4117]; Santos, N. [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
We report the discovery of HD 110113 b (TESS object of interest-755.01), a transiting mini-Neptune exoplanet on a 2.5-d orbit around the solar-analogue HD 110113 (Teff = 5730 K). Using TESS photometry and High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities gathered by the NCORES program, we find that HD 110113 b has a radius of 2.05 ± 0.12 R⊕ and a mass of 4.55 ± 0.62 M⊕. The resulting density of 2.90+0.75−0.59 g cm−3 is significantly lower than would be expected from a pure-rock world; therefore HD 110113 b must be a mini-Neptune with a significant volatile atmosphere. The high incident flux places it within the so-called radius valley; however, HD 110113 b was able to hold on to a substantial (0.1–1 per cent) H–He atmosphere over its ∼4 Gyr lifetime. Through a novel simultaneous Gaussian process fit to multiple activity indicators, we were also able to fit for the strong stellar rotation signal with period 20.8 ± 1.2 d from the RVs and confirm an additional non-transiting planet, HD 110113 c, which has a mass of 10.5 ± 1.2 M⊕ and a period of 6.744+0.008−0.009 d.
Restringido
A remnant planetary core in the hot-Neptune desert
(Springer Nature Research Journals, 2020-07-01) Armstrong, D. J.; López, Théo A.; Adibekyan, V.; Booth, R. A.; Bryant, E. M.; Collins, K. A.; Deleuil, M.; Emsenhuber, A.; Huang, C. X.; King, G. W.; Lillo Box, J.; Lissauer, J. J.; Matthews, E.; Mousis, O.; Nielsen, L. D.; Osborn, Hugh P.; Otegi, Jon F.; Santos, Nuno C.; Sousa, S. G.; Stassun, K. G.; Veras, D.; Ziegler, C.; Acton, J. S.; Almenara, J. M.; Anderson, D. R.; Barrado, D.; Barros, S. C. C.; Bayliss, D.; Belardi, C.; Bouchy, F.; Briceño, C.; Brogi, M.; Brown, D. J. A.; Burleigh, M. R.; Casewell, S. L.; Chausev, A.; Ciardi, D. R.; Collins, K. I.; Colón, K. D.; Cooke, B. F.; Crossfield, J. M.; Díaz, R. F.; Delgado Mena, E.; Gandhi, O. D. S.; Gill, Samuel; Gonzales, E. J.; Goad, M. R.; Günther, M. N.; Helled, R.; Hojjatpanah, S.; Howell, Steve B.; Jackman, J.; Jenkins, J. S.; Jenkins, J. M.; Jensen, E. L. N.; Kennedy, G. M.; Latham, D. W.; Law, N.; Osborn, M.; Pollacco, D.; Queloz, D.; Raynard, L.; Ricker, George; Rowden, P.; Santerne, A.; Schlieder, Joshua; Seager, S.; Sha, L.; Tan, T. G.; Tilbrook, R. H.; Ting, E.; Udry, S.; Vanderspek, R.; Watson, C. A.; West, R. G.; Wilson, P. A.; Winn, J. N.; Wheatley, P.; Villaseñor, J. N.; Vines, J. I.; Zhan, Z.; National Aeronautics and Space Administration (NASA); Fundação para a Ciência e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); Science and Technology Facilities Council (STFC); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Collins, K. A. [0000-0002-4317-142X]; Lillo Box, J. [0000-0003-3742-1987]; Matthews, E. [0000-0003-0593-1560]; Sousa, S. [0000-0002-3631-6440]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune 'desert'(1,2)(a region in mass-radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b(3), which is thought to have an unusually massive core, and recent discoveries such as LTT9779b(4)and NGTS-4b(5), on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune's but an anomalously large mass of39.1-2.6+2.7Earth masses and a density of5.2-0.8+0.7grams per cubic centimetre, similar to Earth's. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than3.9-0.9+0.8 per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation(6). Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.
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.
Acceso Abierto
The EChO science case
(Springer Link, 2015-11-29) Tinetti, G.; Drossart, P.; Eccleston, P.; Hartogh, P.; Isaak, K.; Linder, M.; Lovis, C.; Micela, G.; Olliver, M.; Puig, L.; Ribas, I.; Sicardy, B.; Kehoe, T.; Deeg, H.; Petrov, R.; Doel, P.; Tennyson, J.; Filacchione, G.; Varley, R.; Temple, J.; Lahav, O.; MacTavish, C.; Wisniowski, T.; Piccioni, G.; Guàrdia, J.; Cavarroc, C.; Jones, G.; Ade, P.; Sanromá, E.; Frith, J.; Lognonné, P.; Pantin, E.; Crook, J.; Colomé, J.; Allard, F.; Azzollini, R.; Burston, R.; Parviainen, H.; Malaguti, G.; Gerard, J. C.; Stamper, R.; Barrado, D.; Maldonado, J.; Morales, J. C.; Yurchenko, S. N.; Lagage, P. O.; Prinja, R.; Koskinen, T.; Waldmann, I.; Venot, O.; Heiter, U.; Lim, T.; Pace, E.; Moya Bedon, A.; Irwin, P.; Michaut, C.; Monteiro, M.; Jones, H.; Wawer, P.; Fouqué, P.; Widemann, T.; Alonso Floriano, F. J.; Eiroa, C.; Savini, G.; Stixrude, L.; Damasso, M.; Rataj, M.; Glasse, A.; Koskinen, T.; Bulgarelli, A.; Ciaravella, A.; Hollis, M.; Schmider, F. X.; Kerschbaum, F.; Licandro Goldaracena, J.; Claret, A.; Rocchetto, M.; López Valverde, Miguel Ángel; Fossey, S.; Leto, G.; Ramos Zapata, G.; Beaulieu, J. P.; Balado, A.; Luzzi, D.; Rebordao, J.; Encrenaz, T.; Adriani, A.; Alcala, J.; Guedel, M.; Morales Calderón, M.; Peña Ramírez, K. Y.; Herrero, Enrique; Focardi, M.; Montalto, M.; Wright, G.; Danielski, C.; Burleigh, M. R.; Medvedev, A.; Murgas Alcaino, F.; Chadney, J.; Bowles, N.; Maxted, Pierre; Kerschbaum, F.; Ward Thompson, D.; Laken, B.; Börne, P.; Christian Jessen, N.; Dominic, C.; López Morales, M.; Miles Paez, P.; Achilleos, N.; Biondi, D.; White, G.; Heredero, R. L.; De Kok, R.; Frith, J.; Grodent, D.; Rank Lüftinger, T.; Scholz, A.; Villaver, E.; Dobrijévic, M.; Alard, C.; Demangeon, O. D. S.; De Witt, J.; Machado, P.; Cordier, D.; Charnoz, S.; Rodler, F.; Gerard, J. C.; Sousa, S. G.; Viti, S.; Cole, R.; Blecka, M.; Barber, R. J.; Middleton, K.; Griffin, M.; Giro, E.; Cho, J.; Covino, E.; Turrini, D.; Moro Martín, A.; Decin, L.; Ramos, A. A.; Schrader, J. R.; Massi, F.; Abe, L.; Mauskopf, P.; Batista, V.; Agnor, C.; Bordé, P.; Fabrizio, N.; Bakos, G.; Rengel, M.; Gustin, J.; Hueso, R.; Fernández Hernández, Maite; Ray, T.; Claudi, R.; Femenía Castella, B.; Rebolo, R.; Sethenadh, J.; Luntzer, A.; Mueller Wodarg, I.; Delgado Mena, E.; Brown, L.; De Sio, A.; González Hernández, J.; Selsis, F.; Leconte, J.; Del Vecchio, C.; Budaj, J.; Scandariato, G.; Pagano, I.; García Piquer, A.; Guillot, T.; Terenzi, L.; Tabernero, H. M.; Forget, F.; Hargrave, P.; North, C.; Heyrovsky, D.; Cerulli, R.; Adybekian, V.; Read, P.; Pinsard, Frederic; Parmentier, V.; Collura, A.; Hubert, B.; Lanza, N.; Graczyk, R.; Fouqué, P.; Giuranna, M.; Valdivieso, M. L.; Pérez Hoyos, S.; Andersen, A.; Mall, U.; Buchhave, L. A.; Yelle, R.; Rickman, H.; Ballerini, P.; Affer, L.; Maruquette, J. B.; Sánchez Béjar, V. J.; Nelson, Richard; Fletcher, L.; Radioti, A.; Turrini, D.; Montes, D.; Gizon, L.; Galand, M.; Gómez, H.; Eymet, V.; Esposito, M.; Smith, A.; Morello, G.; Allende Prieto, C.; Justtanot, K.; Bryson, I.; Pallé, E.; Amado, P. J.; Figueira, P.; Shore, Steven; Focardi, M.; Strazzulla, G.; Giani, E.; Pietrzak, R.; González Merino, B.; Lo Cicero, Ugo; Gaulme, P.; Sozzetti, A.; Femenía Castella, B.; Maillard, J. P.; Cabral, A.; Iro, N.; Magnes, W.; Pinfield, David J.; Swain, M.; Showman, A.; Bellucci, G.; Kerins, E.; Maurin, A. S.; Poretti, E.; Boisse, I.; Barton, E. J.; Kervella, P.; Guio, P.; Norgaard Nielsen, H. U.; Bézard, B.; Montañés Rodríguez, P.; Banaszkiewicz, M.; Kovács, G.; Baffa, C.; Del Val Borro, M.; Belmonte Avilés, J. A.; Palla, F.; Hersant, F.; Correira, A.; Yung, Y.; Cockell, Charles S.; Vinatier, S.; Pilat Lohinger, E.; Krupp, N.; Orton, G.; Vakili, F.; Pezzuto, S.; Di Giorgio, A.; Waltham, D.; Testi, L.; Stiepen, A.; Deroo, P.; Capria, M. T.; Eales, S.; Irshad, R.; Stolarski, M.; Zapatero Osorio, M. R.; Swinyard, B.; Griffith, C.; Winek, W.; Bouy, H.; Thompson, S.; Maggio, A.; Moses, J.; Liu, S. J.; Lithgow Bertelloni, C.; Coudé du Foresto, V.; Martín Torres, Javier; Fletcher, L.; Barlow, M.; Coustenis, A.; Berry, D.; López Puertas, M.; Banaszkiewicz, M.; Lundgaard Rasmussen, I.; Hoogeveen, Ruud; Morais, H.; Watkins, C.; Oliva, E.; Scuderi, S.; Aylward, A.; Bonford, B.; Sitek, P.; Haigh, J.; Prisinzano, L.; Soret, L.; Wawrzaszk, A.; Lammer, H.; Figueira, P.; Gianotti, F.; Readorn, K.; Tanga, P.; Israelian, G.; Gesa, L.; Peralta, J.; Gómez Leal, I.; Cassan, A.; Tecsa, M.; Tessenyi, M.; Pancrazzi, M.; Coates, A.; Gambicorti, L.; Gear, W.; Winter, B.; Piskunov, N.; Álvarez Iglesias, C. A.; Polichtchouk, I.; Altieri, F.; Ottensamer, R.; Watson, D.; Rezac, L.; Vandenbussche, B.; Waters, R.; Dorfi, E.; Morgante, G.; Pascale, E.; Hornstrup, A.; Snellen, Ignas; Lodieu, N.; Lellouch, E.; Espinoza Contreras, M.; Jarchow, C.; Agúndez, Marcelino; Filacchione, G.; Abreu, M.; Grassi, D.; Tingley, B. W.; Sánchez Lavega, Agustín; Tozzi, A.; Sanz Forcada, J.; Kipping, D.; Chamberlain, S.; Trifoglio, M.; Barstow, J. K.; Santos, Nuno C.; Gillon, M.; Hébrard, E.; Cecchi Pestellini, C.; Fossey, S.; García López, Ramón; Thrastarson, H.; Rees, J. M.; Selig, A.; Galand, M.; Jacquemoud, S.; Branduardi Raymont, Graziella; Rebordao, J. [0000-0002-7418-0345]; Kerschbaum, F. [0000-0001-6320-0980]; Abreu, M. [0000-0002-0716-9568]; Tabernero, H. [0000-0002-8087-4298]; López Puertas, M. [0000-0003-2941-7734]; Jacquemoud, S. [0000-0002-1500-5256]; Tennyson, J. [0000-0002-4994-5238]; Focardi, M. [0000-0002-3806-4283]; Leto, G. [0000-0002-0040-5011]; Lodieu, N. [0000-0002-3612-8968]; Tinetti, G. [0000-0001-6058-6654]; Danielski, C. [0000-0002-3729-2663]; Hornstrup, A. [0000-0002-3363-0936]; Kervella, P. [0000-0003-0626-1749]; Sánchez Bejar, V. [0000-0002-5086-4232]; López Heredero, R. [0000-0002-2197-8388]; Sanz Forcada, J. [0000-0002-1600-7835]; Rickman, H. [0000-0002-9603-6619]; Maggio, A. [0000-0001-5154-6108]; Medved, A. [0000-0003-2713-8977]; Tinetti, G. [0000-0001-6058-6654]; Fletcher, L. [0000-0001-5834-9588]; Haigh, J. [0000-0001-5504-4754]; Bakos, G. [0000-0001-7204-6727]; Stixrude, L. [0000-0003-3778-2432]; Amado, P. J. [0000-0002-8388-6040]; Martín Torres, J. [0000-0001-6479-2236]; Correira, A. [0000-0002-8946-8579]; Yurchenko, S. [0000-0001-9286-9501]; Rataj, M. [0000-0002-2978-9629]; Guedel, M. [0000-0001-9818-0588]; Piskunov, N. [0000-0001-5742-7767]; Filacchione, G. [0000-0001-9567-0055]; Adibekyan, V. [0000-0002-0601-6199]; Budaj, J. [0000-0002-9125-7340]; Poretti, E. [0000-0003-1200-0473]; Pascale, E. [0000-0002-3242-8154]; Claudi, R. [0000-0001-7707-5105]; Piccioni, G. [0000-0002-7893-6808]; Ribas, I. [0000-0002-6689-0312]; Sanroma, E. [0000-0001-8859-7937]; Agundez, M. [0000-0003-3248-3564]; Montes, D. [0000-0002-7779-238X]; Lognonne, P. [0000-0002-1014-920X]; Abreu, M. [0000-0002-0716-9568]; Montes, D. [0000-0002-7779-238X]; Morais, M. H. [0000-0001-5333-2736]; Tanga, P. [0000-0002-2718-997X]; Peralta, J. [0000-0002-6823-1695]; Hueso, R. [0000-0003-0169-123X]; Leto, G. [0000-0002-0040-5011]; Morales, J. C. [0000-0003-0061-518X]; Pérez Hoyos, S. [0000-0002-2587-4682]; Santos, N. [0000-0003-4422-2919]; Lithgow Bertelloni, C. [0000-0003-0924-6587]; Delgado, M. E. [0000-0003-4434-2195]; Barlow, M. [0000-0002-3875-1171]; Deeg, H. [0000-0003-0047-4241]; Bouy, H. [0000-0002-7084-487X[; Grassi, D. [0000-0003-1653-3066]; Figueira, P. [0000-0001-8504-283X]; Barton, E. [0000-0001-5945-9244]; Coates, A. [0000-0002-6185-3125]; García Ramón, J. [0000-0002-8204-6832]; Watson, D. [0000-0002-4465-8264]; Morales Calderon, M. [0000-0001-9526-9499]; Demangeon, O. [0000-0001-7918-0355]; Ray, T. [0000-0002-2110-1068]; Guio, P. [0000-0002-1607-5862]; Gillon, M. [0000-0003-1462-7739]; Bulgarelli, A. [0000-0001-6347-0649]; Prisinzano, L. [0000-0002-8893-2210]; Barstow, J. [0000-0003-3726-5419]; Pancrazzi, M. [0000-0002-3789-2482]; Barrado Navascues, D. [0000-0002-5971-9242]; Balado, A. [0000-0003-4268-2516]; Malaguti, G. [0000-0001-9872-3378]; Zapatero Osorio, M. R. [0000-0001-5664-2852]; Affer, L. [0000-0001-5600-3778]; Ciaravella, A. [0000-0002-3127-8078]; Guillot, T. [0000-0002-7188-8428]; Altieri, F. [0000-0002-6338-8300]; Covino, E. [0000-0002-6187-6685]; Venot, O. [0000-0003-2854-765X]; López Valverde, M. A. [0000-0002-7989-4267]; Cabral, A. [0000-0002-9433-871X]; Selsis, F. [0000-0001-9619-5356]; Turrini, D. [0000-0002-1923-7740]; Ward Thompson, D. [0000-0003-1140-2761]; Rebolo, R. [0000-0003-3767-7085]; Damasso, M. [0000-0001-9984-4278]; Tizzi, A. [0000-0002-6725-3825]; Morgante, G. [0000-0001-9234-7412]; Pena Ramírez, K. [0000-0002-5855-401X]; Galand, M. [0000-0001-5797-914X]; Pace, E. [0000-0001-5870-1772]; Pilat Lohinger, E. [0000-0002-5292-1923]; Sánchez Lavega, A. [0000-0001-7234-7634]; Waldmann, I. [0000-0002-4205-5267]; Claret, A. [0000-0002-4045-8134]; Olivia, E. [0000-0002-9123-0412]; Kovacs, G. [0000-0002-2365-2330]; Gómez, H. [0000-0003-3398-0052]; Monteiro, M. [0000-0001-5644-0898]; Bellucci, G. [0000-0003-0867-8679]; Baffa, C. [0000-0002-4935-100X]; Scholz, A. [0000-0001-8993-5053]; Bezard, B. [0000-0002-5433-5661]; Scuderi, Salvatore [0000-0002-8637-2109]; Hersant, F. [0000-0002-2687-7500]; Maldonado, J. [0000-0002-4282-1072]; Gear, W. [0000-0001-6789-6196]; Sousa, S. [0000-0001-9047-2965]; Irwin, P. [0000-0002-6772-384X]; Pinfield, D. [0000-0002-7804-4260]; Kipping, D. [0000-0002-4365-7366]; Ade, P. [0000-0002-5127-0401]; Vandenbussche, B. [0000-0002-1368-3109]; Burleigh, M. [0000-0003-0684-7803]; Chadney, J. [0000-0002-5174-2114]; Moro Martín, A. [0000-0001-9504-8426]; Scandariato, G. [0000-0003-2029-0626]; Rodríguez, P. [0000-0002-6855-9682]; Maldonado, J. [0000-0002-2218-5689]; Michaut, C. [0000-0002-2578-0117]; Pérez Hoyos, S. [0000-0001-9797-4917]
The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune—all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10−4 relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength coverage of at least 0.55 to 11 μm with a goal of covering from 0.4 to 16 μm. Only modest spectral resolving power is needed, with R ~ 300 for wavelengths less than 5 μm and R ~ 30 for wavelengths greater than this. The transit spectroscopy technique means that no spatial resolution is required. A telescope collecting area of about 1 m2 is sufficiently large to achieve the necessary spectro-photometric precision: for the Phase A study a 1.13 m2 telescope, diffraction limited at 3 μm has been adopted. Placing the satellite at L2 provides a cold and stable thermal environment as well as a large field of regard to allow efficient time-critical observation of targets randomly distributed over the sky. EChO has been conceived to achieve a single goal: exoplanet spectroscopy. The spectral coverage and signal-to-noise to be achieved by EChO, thanks to its high stability and dedicated design, would be a game changer by allowing atmospheric composition to be measured with unparalleled exactness: at least a factor 10 more precise and a factor 10 to 1000 more accurate than current observations. This would enable the detection of molecular abundances three orders of magnitude lower than currently possible and a fourfold increase from the handful of molecules detected to date. Combining these data with estimates of planetary bulk compositions from accurate measurements of their radii and masses would allow degeneracies associated with planetary interior modelling to be broken, giving unique insight into the interior structure and elemental abundances of these alien worlds. EChO would allow scientists to study exoplanets both as a population and as individuals. The mission can target super-Earths, Neptune-like, and Jupiter-like planets, in the very hot to temperate zones (planet temperatures of 300–3000 K) of F to M-type host stars. The EChO core science would be delivered by a three-tier survey. The EChO Chemical Census: This is a broad survey of a few-hundred exoplanets, which allows us to explore the spectroscopic and chemical diversity of the exoplanet population as a whole. The EChO Origin: This is a deep survey of a subsample of tens of exoplanets for which significantly higher signal to noise and spectral resolution spectra can be obtained to explain the origin of the exoplanet diversity (such as formation mechanisms, chemical processes, atmospheric escape). The EChO Rosetta Stones: This is an ultra-high accuracy survey targeting a subsample of select exoplanets. These will be the bright “benchmark” cases for which a large number of measurements would be taken to explore temporal variations, and to obtain two and three dimensional spatial information on the atmospheric conditions through eclipse-mapping techniques. If EChO were launched today, the exoplanets currently observed are sufficient to provide a large and diverse sample. The Chemical Census survey would consist of > 160 exoplanets with a range of planetary sizes, temperatures, orbital parameters and stellar host properties. Additionally, over the next 10 years, several new ground- and space-based transit photometric surveys and missions will come on-line (e.g. NGTS, CHEOPS, TESS, PLATO), which will specifically focus on finding bright, nearby systems. The current rapid rate of discovery would allow the target list to be further optimised in the years prior to EChO’s launch and enable the atmospheric characterisation of hundreds of planets.
Acceso Abierto
The Gaia -ESO Survey: A new approach to chemically characterising young open clusters: I. Stellar parameters, and iron-peak, α -, and proton-capture elements
(EDP Sciences, 2020-01-31) Baratella, M.; D´Orazi, V.; Carraro, G.; Desidera, S.; Randich, S.; Magrini, L.; Adibekyan, V.; Smiljanic, R.; Spina, L.; Tsantaki, M.; Tautvaisilenè, G.; Sousa, S. G.; Jofre, P.; Jiménez Esteban, F. M.; Delgado Mena, E.; Martell, S.; Van der Swaelmen, M.; Roccatagliata, V.; Gilmore, G.; Alfaro, Emilio J.; Bayo, A.; Bensby, T.; Bragaglia, A.; Franciosini, E.; Gonneau, A.; Heiter, U.; Hourihane, A.; Jeffries, R. D.; Koposov, S. E.; Morbidelli, L.; Prisinzano, L.; Sacco, Giuseppe Germano; Sbordone, L.; Worley, Christopher; Zaggia, S.; Lewis, J.; European Commission (EC); Leverhulme Trust; Fundacao para a Ciencia e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); Jeffries, R. D. [0000-0001-5668-1288]; Magrini, L. [0000-0003-4486-6802]; Mena, E. D. [0000-0003-4434-2195]; Smiljanic, R. [0000-0003-0942-7855]; Koposov, S. [0000-0003-2644-135X]; Carraro, G. [0000-0002-0155-9434]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. Open clusters are recognised as excellent tracers of Galactic thin-disc properties. At variance with intermediate-age and old open clusters, for which a significant number of studies is now available, clusters younger than ≲ 150 Myr have been mostly overlooked in terms of their chemical composition until recently (with few exceptions). On the other hand, previous investigations seem to indicate an anomalous behaviour of young clusters, which includes (but is not limited to) slightly sub-solar iron (Fe) abundances and extreme, unexpectedly high barium (Ba) enhancements. Aims. In a series of papers, we plan to expand our understanding of this topic and investigate whether these chemical peculiarities are instead related to abundance analysis techniques. Methods. We present a new determination of the atmospheric parameters for 23 dwarf stars observed by the Gaia-ESO survey in five young open clusters (τ < 150 Myr) and one star-forming region (NGC 2264). We exploit a new method based on titanium (Ti) lines to derive the spectroscopic surface gravity, and most importantly, the microturbulence parameter. A combination of Ti and Fe lines is used to obtain effective temperatures. We also infer the abundances of Fe » I, Fe » II, Ti » I, Ti » II, Na » I, Mg » I, Al » I, Si » I, Ca » I, Cr » I, and Ni » I. Results. Our findings are in fair agreement with Gaia-ESO iDR5 results for effective temperatures and surface gravities, but suggest that for very young stars, the microturbulence parameter is over-estimated when Fe lines are employed. This affects the derived chemical composition and causes the metal content of very young clusters to be under-estimated. Conclusions. Our clusters display a metallicity [Fe/H] between +0.04 ± 0.01 and +0.12 ± 0.02; they are not more metal poor than the Sun. Although based on a relatively small sample size, our explorative study suggests that we may not need to call for ad hoc explanations to reconcile the chemical composition of young open clusters with Galactic chemical evolution models. © ESO 2020.
Acceso Abierto
The Gaia -ESO Survey: Calibrating the lithium-age relation with open clusters and associations: I. Cluster age range and initial membership selections
(EDP Sciences, 2020-11-05) Gutiérrez Albarrán, M. L.; Montes, D.; Gómez Garrido, M.; Tabernero, H. M.; González Hernández, J. I.; Marfil, E.; Frasca, A.; Lanzafame, A. C.; Klutsch, A.; Franciosini, E.; Randich, S.; Smiljanic, R.; Korn, A. J.; Gilmore, G.; Alfaro, Emilio J.; Baratella, M.; Bayo, A.; Bensby, T.; Bonito, R.; Carraro, G.; Delgado Mena, E.; Feltzing, S.; Gonneau, A.; Heiter, U.; Hourihane, A.; Jiménez Esteban, F. M.; Jofre, P.; Masseron, T.; Monaco, L.; Morbidelli, L.; Prisinzano, L.; Roccatagliata, V.; Sousa, S. G.; Van der Swaelmen, M.; Worley, Charlotte C.; Zaggia, S.; Ministerio de Economía y Competitividad (MINECO); European Commission (EC); Istituto Nazionale di Astrofisica (INAF); Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR); Agencia Estatal de Investigación (AEI); Fundação para a Ciência e a Tecnologia (FCT); Leverhulme Trust; 0000-0002-7569-3513; 0000-0002-7779-238X; 0000-0002-8087-4298; 0000-0002-0264-7356; 0000-0001-8907-4775; 0000-0002-0474-0896; 0000-0001-7869-3888; 0000-0003-3969-0232; 0000-0003-2438-0899; 0000-0003-0942-7855; 0000-0003-3978-1409; 0000-0001-9297-7748; 0000-0002-0155-9434; 0000-0002-3148-9836
Context. Previous studies of open clusters have shown that lithium depletion is not only strongly age dependent but also shows a complex pattern with other parameters that is not yet understood. For pre- and main-sequence late-type stars, these parameters include metallicity, mixing mechanisms, convection structure, rotation, and magnetic activity. Aims. We perform a thorough membership analysis for a large number of stars observed within the Gaia-ESO survey (GES) in the field of 20 open clusters, ranging in age from young clusters and associations, to intermediate-age and old open clusters. Methods. Based on the parameters derived from the GES spectroscopic observations, we obtained lists of candidate members for each of the clusters in the sample by deriving radial velocity distributions and studying the position of the kinematic selections in the EW(Li)-versus-Teff plane to obtain lithium members. We used gravity indicators to discard field contaminants and studied [Fe/H] metallicity to further confirm the membership of the candidates. We also made use of studies using recent data from the Gaia DR1 and DR2 releases to assess our member selections. Results. We identified likely member candidates for the sample of 20 clusters observed in GES (iDR4) with UVES and GIRAFFE, and conducted a comparative study that allowed us to characterize the properties of these members as well as identify field contaminant stars, both lithium-rich giants and non-giant outliers. Conclusions. This work is the first step towards the calibration of the lithium-age relation and its dependence on other GES parameters. During this project we aim to use this relation to infer the ages of GES field stars, and identify their potential membership to young associations and stellar kinematic groups of different ages. © ESO 2020.