A high-resolution line survey of IRC+10216 with Herschel/HIFI First results: Detection of warm silicon dicarbide (SiC2)
Artikel i vetenskaplig tidskrift, 2010

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 similar to 2 x 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 similar to 204 K and a source-averaged column density of similar to 6.4 x 10(15) cm(-2). Furthermore, the high quality of the HIFI data set was used to improve the spectroscopic rotational constants of SiC2.

stars: carbon

emission

molecular-spectroscopy

cologne database

identification

chemistry

submillimeter hcn laser

laboratory measurement

bure observations

line: identification

stars: AGB and post-AGB

astrochemistry

dust formation zone

envelope

stars: individual: IRC+10216

Författare

J. Cernicharo

CSIC-INTA - Centro de Astrobiologia (CAB)

Lbfm Waters

Astronomical Institute Anton Pannekoek

KU Leuven

L. Decin

KU Leuven

Astronomical Institute Anton Pannekoek

P. Encrenaz

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

Aggm Tielens

Leiden University

M. Agundez

CSIC-INTA - Centro de Astrobiologia (CAB)

Observatoire de Paris-Meudon

Elvire De Beck

KU Leuven

Holger Muller

Universität zu Köln

J. R. Goicoechea

CSIC-INTA - Centro de Astrobiologia (CAB)

M. J. Barlow

University College London (UCL)

A. Benz

Eidgenössische Technische Hochschule Zürich (ETH)

N. Crimier

CSIC-INTA - Centro de Astrobiologia (CAB)

F. Daniel

CSIC-INTA - Centro de Astrobiologia (CAB)

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

A. M. di Giorgio

Universita degli Studi di Roma Tor Vergata

M. Fich

University of Waterloo

T. Gaier

Jet Propulsion Laboratory, California Institute of Technology

P. Garcia-Lario

European Space Astronomy Centre

A. de Koter

Sterrekundig Instituut Utrecht

Astronomical Institute Anton Pannekoek

T. Khouri

Astronomical Institute Anton Pannekoek

René Liseau

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

R. Lombaert

KU Leuven

N. Erickson

University of Massachusetts

J. R. Pardo

CSIC-INTA - Centro de Astrobiologia (CAB)

J. C. Pearson

Jet Propulsion Laboratory, California Institute of Technology

R. Shipman

SRON Netherlands Institute for Space Research

C. S. Contreras

CSIC-INTA - Centro de Astrobiologia (CAB)

D. Teyssier

European Space Astronomy Centre

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 521 Article Number: L8- L8

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1051/0004-6361/201015150