Analysis of Radio Astronomical Data of the Negative Ion C 6 H - in IRC +10 216

Radio astronomical data of C 6 H - 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) × 10 12 cm -2 and the excitation temperature of 32 ± 3 K, with an assumed source size of 30'' ± 3''. The abundance of C 6 H - was estimated to be 8.6% of C 6 H. The observed line shapes of C 6 H - and C 6 H indicate that the distribution of C 6 H - is more present in the inner region than C 6 H. The production mechanism of C 6 H - is discussed.