Analysis of Radio Astronomical Data of the Negative Ion C6H– in IRC +10 216

Radio astronomical data of C6H- observed with the Nobeyama 45 m and IRAM 30 m telescopes have been analyzed by the local thermodynamic equilibrium approximation to give the column density of (6.1-8.0) × 1012 cm-2 and the excitation temperature of 32 ± 3 K, with an assumed source size of 30'' ± 3''. The abundance of C6H- was estimated to be 8.6% of C6H. The observed line shapes of C6H - and C6H indicate that the distribution of C 6H- is more present in the inner region than C6H. The production mechanism of C6H- is discussed.