Detection of C6H- toward the low-mass protostar IRAS 04368+2557 in L1527

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 C6H2 in L1527. This is the first detection of these three species in star-forming regions. The column density of C6H- is (5.8 +/- 1.8) x 10(10) cm(-2), which is comparable to that in TMC-1, although the column density of C6H in L1527 is about 1/5 of that in TMC-1. Hence, the N((CH-)-H-6)/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.