Universität zu Köln

Gong, Y., Henkel, C., Spezzano, S., Thorwirth, S., Menten, K. M., Wyrowski, F., Mao, R. Q. and Klein, B. (2015). A 1.3 cm line survey toward IRC+10216. Astron. Astrophys., 574. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. IRC + 10216 is the prototypical carbon star exhibiting an extended molecular circumstellar envelope. Its spectral properties are therefore the template for an entire class of objects. Aims. The main goal is to systematically study the lambda similar to 1.3 cm spectral line characteristics of IRC + 10216. Methods. We carried out a spectral line survey with the Effelsberg-100 m telescope toward IRC + 10216. It covers the frequency range between 17.8 GHz and 26.3 GHz (K-band). Results. In the circumstellar shell of IRC + 10216, we find 78 spectral lines, among which 12 remain unidentified. The identified lines are assigned to 18 different molecules and radicals. A total of 23 lines from species known to exist in this envelope are detected for the first time outside the solar system and there are additional 20 lines first detected in IRC + 10216. The potential orgin of U lines is also discussed. Assuming local thermodynamic equilibrium (LTE), we then determine rotational temperatures and column densities of 17 detected molecules. Molecular abundances relative to H-2 are also estimated. A non-LTE analysis of NH3 shows that the bulk of its emission arises from the inner envelope with a kinetic temperature of 70 +/- 20 K. Evidence for NH3 emitting gas with higher kinetic temperature is also obtained, and potential abundance differences between various C-13-bearing isotopologues of HC5N are evaluated. Overall, the isotopic C-12/C-13 ratio is estimated to be 49 +/- 9. Finally, a comparison of detected molecules in the lambda similar to 1.3 cm range with the dark cloud TMC-1 indicates that silicate-bearing molecules are more predominant in IRC + 10216.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Gong, Y. UNSPECIFIED UNSPECIFIED UNSPECIFIED Henkel, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Spezzano, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Thorwirth, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Menten, K. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wyrowski, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mao, R. Q. UNSPECIFIED UNSPECIFIED UNSPECIFIED Klein, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-413052
DOI:	10.1051/0004-6361/201424819
Journal or Publication Title:	Astron. Astrophys.
Volume:	574
Date:	2015
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CIRCUMSTELLAR ENVELOPE; SPECTRAL SCAN; MOLECULAR-EMISSION; C-13 ISOTOPOMERS; NEARBY GALAXIES; HOT AMMONIA; WATER-VAPOR; IRC +10216; DENSE GAS; CARBON Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/41305