Cernicharo, J;
Waters, LBFM;
Decin, L;
Encrenaz, P;
Tielens, AGGM;
Agúndez, M;
De Beck, E;
... Teyssier, D; + view all
(2010)
A high-resolution line survey of IRC +10216 with Herschel/HIFI: First results: Detection of warm silicon dicarbide (SiC₂).
Astronomy & Astrophysics
, 521
, Article L8. 10.1051/0004-6361/201015150.
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Abstract
We present the first results of a high-spectral-resolution survey of the carbon-rich evolved star IRC+10216 that was carried out with the HIFI spectrometer onboard Herschel. This survey covers all HIFI bands, with a spectral range from 488 to 1901 GHz. In this letter we focus on the band-1b spectrum, in a spectral range 554.5–636.5 GHz, where we identified 130 spectral features with intensities above 0.03 K and a signal-to-noise ratio >5. Detected lines arise from HCN, SiO, SiS, CS, CO, metal-bearing species and, surprisingly, silicon dicarbide (SiC2). We identified 55 SiC2 transitions involving energy levels between 300 and 900 K. By analysing these rotational lines, we conclude that SiC2 is produced in the inner dust formation zone, with an abundance of ~ 2 × 10-7 relative to molecular hydrogen. These SiC2 lines have been observed for the first time in space and have been used to derive an SiC2 rotational temperature of ~204 K and a source-averaged column density of ~ 6.4 × 1015 cm-2. Furthermore, the high quality of the HIFI data set was used to improve the spectroscopic rotational constants of SiC2.
| Type: | Article |
|---|---|
| Title: | A high-resolution line survey of IRC +10216 with Herschel/HIFI: First results: Detection of warm silicon dicarbide (SiC₂) |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1051/0004-6361/201015150 |
| Publisher version: | https://doi.org/10.1051/0004-6361/201015150 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | stars: individual: IRC+10216 / stars: carbon / stars: AGB and post-AGB / line: identification / astrochemistry |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10095294 |
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