Issue |
A&A
Volume 606, October 2017
|
|
---|---|---|
Article Number | L5 | |
Number of page(s) | 5 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361/201731672 | |
Published online | 09 October 2017 |
Discovery of methyl silane and confirmation of silyl cyanide in IRC +10216⋆
1 Group of Molecular Astrophysics, ICMM, CSIC, C/ Sor Juana Inés de La Cruz 3, 28049 Madrid, Spain
e-mail: jose.cernicharo@csic.es
2 Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 St-Martin d’ Hères, France
3 Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
4 Instituto de Radioastronomía Milimétrica, Av. Divina Pastora 7, Local 20, 18012 Granada, Spain
5 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, and School of Engineering & Applied Sciences, Harvard University, Cambridge, MA 02138, USA
6 Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, 47011 Valladolid, Spain
Received: 29 July 2017
Accepted: 4 September 2017
We report the discovery in space of methyl silane, CH3SiH3, from observations of ten rotational transitions between 80 and 350 GHz (Ju from 4 to 16) with the IRAM 30 m radio telescope. The molecule was observed in the envelope of the C-star IRC +10216. The observed profiles and our models for the expected emission of methyl silane suggest that the it is formed in the inner zones of the circumstellar envelope, 1−40 R∗, with an abundance of (0.5−1) × 10-8 relative to H2. We also observed several rotational transitions of silyl cyanide (SiH3CN), confirming its presence in IRC +10216 in particular, and in space in general. Our models indicate that silyl cyanide is also formed in the inner regions of the envelope, around 20 R∗, with an abundance relative to H2 of 6 × 10-10. The possible formation mechanisms of both species are discussed. We also searched for related chemical species but only upper limits could be obtained.
Key words: stars: individual: IRC+10216 / stars: carbon / astrochemistry / stars: AGB and post-AGB
© ESO, 2017
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