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Title: Prevalence of non-aromatic carbonaceous molecules in the inner regions of circumstellar envelopes
Authors: Martínez, Lidia
Santoro, G.
Merino, P.
Accolla, M.
Lauwaet, K.
Sobrado, J. M.
Sabbah, H.
Peláez, R. J.
Herrero, V. J.
Tanarro, I.
Agúndez, Marcelino
Martín Jiménez, Alberto
Otero, Roberto
Ellis, G. J.
Joblin, C.
Cernicharo, J.
Martín-Gago, J. A.
Keywords: Astronomy and planetary science;Chemistry
Issue Date: 21-Oct-2019
Publisher: Nature
DOI: 10.1038/s41550-019-0899-4
Published version:
Citation: Nature Astronomy 4: 97-105(2020)
Abstract: Evolved stars are foundries of chemical complexity, gas and dust that provide the building blocks of planets and life, and dust nucleation first occurs in their photosphere. The circumstellar regions enveloping these stars, despite their importance, remain hidden to many observations, and dust formation processes are therefore still poorly understood. Laboratory astrophysics provides complementary routes to unveil these chemical processes, but most experiments rely on combustion or plasma decomposition of molecular precursors under physical conditions far removed from those in space. To reproduce and characterize the bottom-up dust formation process, we have built an ultra-high vacuum machine combining atomic gas aggregation with advanced in situ characterization techniques. We show that carbonaceous dust analogues that formed from low-pressure gas-phase condensation of carbon atoms in a hydrogen atmosphere, in a ratio of carbon to molecular hydrogen similar to that reported for evolved stars, lead to the formation of amorphous carbon nanograins and aliphatic carbon clusters. Aromatic species and fullerenes do not form effectively under these conditions, raising implications for a revision of the chemical mechanisms taking place in circumstellar envelopes.
Description: Authors and Affiliations Structure of Nanoscopic Systems Group, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Madrid, Spain Lidia Martínez, Gonzalo Santoro, Pablo Merino, Mario Accolla & José A. Martín-Gago Molecular Astrophysics Group, Instituto de Física Fundamental (IFF-CSIC), Madrid, Spain Pablo Merino, Marcelino Agúndez & José Cernicharo IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, Madrid, Spain Koen Lauwaet, Alberto Martín-Jimenez & Roberto Otero Centro de Astrobiología (CAB, INTA-CSIC), Madrid, Spain Jesús Sobrado IRAP, Université de Toulouse, CNRS, CNES, Toulouse, France Hassan Sabbah & Christine Joblin LCAR, Université de Toulouse, UPS-IRSAMC, CNRS, Toulouse, France Hassan Sabbah Molecular Physics Department, Instituto de Estructura de la Materia (IEM-CSIC), Madrid, Spain Ramón J. Pelaez, Victor J. Herrero & Isabel Tanarro Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), Madrid, Spain Gary J. Ellis
E-ISSN: 2397-3366
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