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.

laboratory measurement

stars: individual: IRC+10216

submillimeter hcn laser

dust formation zone

chemistry

envelope

stars: AGB and post-AGB

astrochemistry

molecular-spectroscopy

bure observations

stars: carbon

emission

cologne database

identification

line: identification

Författare

J. Cernicharo

Centro de Astrobiologia (CAB)

Lbfm Waters

KU Leuven

Anton Pannekoek Institute for Astronomy

L. Decin

Anton Pannekoek Institute for Astronomy

KU Leuven

P. Encrenaz

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

Aggm Tielens

Universiteit Leiden

M. Agundez

Centro de Astrobiologia (CAB)

Observatoire de Paris-Meudon

Elvire De Beck

KU Leuven

Holger Muller

Universität zu Köln

J. R. Goicoechea

Centro de Astrobiologia (CAB)

M. J. Barlow

University College London (UCL)

A. Benz

Eidgenössische Technische Hochschule Zürich (ETH)

N. Crimier

Centro de Astrobiologia (CAB)

F. Daniel

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

Centro de Astrobiologia (CAB)

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 (ESA)

A. de Koter

Anton Pannekoek Institute for Astronomy

Sterrekundig Instituut Utrecht

T. Khouri

Anton Pannekoek Institute for Astronomy

René Liseau

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

R. Lombaert

KU Leuven

N. Erickson

University of Massachusetts

J. R. Pardo

Centro de Astrobiologia (CAB)

J. C. Pearson

Jet Propulsion Laboratory, California Institute of Technology

R. Shipman

Netherlands Institute for Space Research (SRON)

C. S. Contreras

Centro de Astrobiologia (CAB)

D. Teyssier

European Space Astronomy Centre (ESA)

Astronomy and Astrophysics

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

Vol. 521 1 Article Number: L8- L8

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1051/0004-6361/201015150