Detection of C 6 H - toward the Low-Mass Protostar IRAS 04368+2557 in L1527

We have detected the J = 7-6, 8-7, and 15-14 lines of C 6 H - 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, C 6 H, and the 8 1,8 -7 1,7 line of C 6 H 2 in L1527. This is the first detection of these three species in star-forming regions. The column density of C 6 H - is (5.8 ± 1.8) × 10 10 cm -2 , which is comparable to that in TMC-1, although the column density of C 6 H in L1527 is about 1/5 of that in TMC-1. Hence, the N (C 6 H - )/ N (C 6 H) 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.