2007ApJ...667L..65S

We have detected the J=7-6, 8-7, and 15-14 lines of C₆H^– toward a low-mass star-forming region of L1527. We have also detected the J=15/2-13/2 and 33/2-31/2 lines of the corresponding neutral species, C₆H, and the 8_1,8-7_1,7 line of C₆H₂in L1527. This is the first detection of these three species in star-forming regions. The column density of C₆H^– is (5.8±1.8)x10¹⁰/cm2, which is comparable to that in TMC-1, although the column density of C₆ H in L1527 is about 1/5 of that in TMC-1. Hence, the N(C₆H^–)/N(C₆H) ratio is 0.093±0.029, which is higher than that in TMC-1 by a factor of 4. This high anion-to-neutral ratio is discussed in terms of a simplified chemical model.