2010/07/26 by J. Cernicharo, L. B. F. M. Waters, L. Decin +33 · 2 citations
Chemistry · Physics and Astronomy · #Analytical Chemistry (journal) #Astrochemistry #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atomic physics #Chemistry #Geometry #Interstellar medium #Line (geometry) #Molecular Spectroscopy and Structure #Optics #Physics #Resolution (logic) #Rotational temperature #Spectral line #Spectral resolution #Spectrometer #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1051/0004-6361/201015150
A&A HIFI Special Issue, 2010
openalex publication_date 2010/07/26 · arxiv created 2010/08/06 · arxiv updated 2015/05/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 <i>Herschel<i/>. 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 <i>><i/>5. Detected lines arise from HCN, SiO, SiS, CS, CO, metal-bearing species and, surprisingly, silicon dicarbide (SiC<sub>2<sub/>). We identified 55 SiC<sub>2<sub/> transitions involving energy levels between 300 and 900 K. By analysing these rotational lines, we conclude that SiC<sub>2<sub/> is produced in the <i>inner<i/> dust formation zone, with an abundance of ~ 2 × 10<sup>-7<sup/> relative to molecular hydrogen. These SiC<sub>2<sub/> lines have been observed for the first time in space and have been used to derive an SiC<sub>2<sub/> rotational temperature of ~204 K and a source-averaged column density of ~ 6.4 × 10<sup>15<sup/> cm<sup>-2<sup/>. Furthermore, the high quality of the HIFI data set was used to improve the spectroscopic rotational constants of SiC<sub>2<sub/>.