A molecular line survey of the extreme carbon star CRL 3068 at millimeter wavelengths

Abstract

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) 12m telescope and the Heinrich Hertz Submillimeter Telescope (SMT) at the 2mm and 1.3mm atmospheric windows. The observations cover the frequency bands from 130--162 GHz and 219.5--267.5 GHz. The typical sensitivities achieved are T_R<15 mK and T_R<7 mK for the ARO 12m 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-C3H, CH3CN, SiC2, and the isotopologues, C17O and C18O, HC15N, HN13C, C33S, C34S, 13CS, 29SiS, and 30SiS 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.

arXiv comment44 pages, 5 figures, Accepted for publication in ApJ

References in corpus (13)

• Imaging the circumstellar envelopes of AGB stars
• Molecular abundances in carbon-rich circumstellar envelopes
• A spectral line survey in the 2 mm and 1.3 mm windows toward the carbon rich envelope of IRC +10216
• The abundance of SiS in circumstellar envelopes around AGB stars
• Probing the mass loss history of carbon stars using CO line and dust continuum emission
• Molecular survey of CRL618
• HI in circumstellar environments
• A spectral line survey of NGC 7027 at millimeter wavelengths
• Chemical Evolution of the Circumstellar Envelopes of Carbon-rich Post-AGB objects
• Observational evidence of the formation of cyanopolyynes in CRL618 through the polimerization of HCN
• A Molecular Line Survey of the Highly Evolved Carbon Star CIT 6
• Carbon-Rich Mira Variables: Radial Velocities and Distances
• The chemistry of compact planetary nebulae

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• Discovery of the cyclic C5H radical in TMC-1
• A Molecular Line Survey of the Carbon-Rich Proto-Planetary Nebula AFGL 2688 in the 3mm and 1.3mm Windows
• Mapping the Central Region of the PPN CRL 618 at Sub-arcsecond Resolution at 350 GHz
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• The spectra of evolved stars at 20--25\,GHz: tracing circumstellar chemistry during the asymptotic giant branch to planetary nebula transition
• GRB Spectra in the complex of synchrotron and Compton processes
• The Abundance of SiC${}_2$ in Carbon Star Envelopes
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