Detection of the Linear Radical HC4N in IRC +10216
Abstract
We report the detection of the linear radical HC4N in the C-rich envelope of IRC +10216. After HCCN, HC4N is the second member of the allenic chain family HC2nN observed in space. The column density of HC4N is found to be 1.5×1012 cm-2. The abundance ratio HC2N/HC4N is 9, a factor of 2 larger than the decrement observed for the cyanopolyynes (HC2n+1N/HC2n+3N). Linear HC4N has a 3Σ electronic ground state and is one of the three low-energy isomeric forms of this molecule. We have searched for the bent and ringed HC4N isomers but could only derive an upper limit to their column densities: <=3×1012 cm-2 (at 3 σ).
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2004
- DOI:
- 10.1086/426439
- arXiv:
- arXiv:astro-ph/0410657
- Bibcode:
- 2004ApJ...615L.145C
- Keywords:
-
- Astrochemistry;
- ISM: Molecules;
- Line: Identification;
- Stars: AGB and Post-AGB;
- Stars: Individual: Alphanumeric: IRC +10216;
- Astrophysics
- E-Print:
- Preprint of 10 pages