A MOLECULAR LINE SURVEY OF THE EXTREME CARBON STAR CRL 3068 AT MILLIMETER WAVELENGTHS

Journal Article · Sat Aug 01 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/700/2/1262; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21313788

Yong, Zhang; Kwok, Sun; Nakashima, Jun-ichi ^[1]

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1. Department of Physics, University of Hong Kong, Pokfulam (Hong Kong)

We present the results of a molecular line survey of the extreme carbon star CRL 3068. The observations were carried out with the Arizona Radio Observatory (ARO) 12 m telescope and the Heinrich Hertz Submillimeter Telescope (SMT) at the {lambda} 2 mm and {lambda} 1.3 mm atmospheric windows. The observations cover the frequency bands from 130 to 162 GHz and 219.5 to 267.5 GHz. The typical sensitivities achieved are T{sub R} < 15 mK and T{sub R} < 7 mK for the ARO 12 m and SMT, respectively. Seventy-two individual emission features belonging to 23 molecular species and isotopologues were detected. Only three faint lines remain unidentified. The species c-C{sub 3}H, CH{sub 3}CN, SiC{sub 2}, and the isotopologues, C{sup 17}O, C{sup 18}O, HC{sup 15}N, HN{sup 13}C, C{sup 33}S, C{sup 34}S, {sup 13}CS, {sup 29}SiS, and {sup 30}SiS are detected in this object for the first time. Rotational-diagram analysis is carried out to determine the column densities and excitation temperatures. The isotopic ratios of the elements C, N, O, S, and Si have also been estimated. The results are consistent with stellar CNO processing and suggest that CRL 3068 is more carbon rich than IRC+10216 and CIT 6. It is also shown that the chemical composition in CRL 3068 is somewhat different from that in IRC+10216 with a more extensive synthesis of cyclic and long-chain molecules in CRL 3068. The results will provide valuable clues for better understanding circumstellar chemistry.

• OSTI ID: 21313788
• Journal Information: Astrophysical Journal, Vol. 700, Issue 2; Other Information: DOI: 10.1088/0004-637X/700/2/1262; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ACETONITRILE
CARBON 13
CARBON MONOXIDE
CARBON STARS
CARBON SULFIDES
CHEMICAL COMPOSITION
EMISSION
GHZ RANGE 100-1000
HYDROCYANIC ACID
INTERSTELLAR GRAINS
ISOTOPE RATIO
NITROGEN 15
OXYGEN 17
OXYGEN 18
SILICON 29
SILICON 30
SILICON SULFIDES
SULFUR 33
SULFUR 34
TELESCOPES