PRODUCTION OF HCN AND C_2H_2 IN COMET C/2002 C1 IKEYA-ZHANG ON UT 2002 APRIL 13.8

摘要

Hydrogen cyanide (HCN) and acetylene (C_2H_2) were detected in comet C/2002 C1 Ikeya-Zhang at infrared wavelengths near 3.0 m using the Cryogenic Echelle Spectrometer (CSHELL) at the NASA Infrared Telescope Facility atop Mauna Kea, HI. Our data set includes observations of the 3.0 m region for 6 dates ranging from UT 2002 March 21.9 (R_h= 0.51 AU) to April 13.9 (R_h = 0.78 AU). In this paper we report results for one date (April 13.8) where the absolute production rates for HCN and C_2H_2 are (3.8 +- 0.5) x 10~(26) molecules s~(-1) and (3.7 +- 0.8) x 10~(26) molecules s~(-1), respectively. These measurements result in a relative abundance of HCN/H_2O = (0.18 +- 0.04)% and C_2H_2 /H_2O = (0.18 +- 0.05)% (Q(H_2O) = (2.1 +- 0.3) x 10~(29)).