ROCKET-BORNE LONG-SLIT ULTRAVIOLET SPECTROSCOPY OF COMET HALE-BOPP

摘要

A sounding rocket observation of comet Hale-Bopp was conducted on 1997 April 6 at 3 51 UT when the comet was at heliocentric and geocentric distances of 0.92 ando 1.39 AU, respectively. The instrument was a telescope and long-slit (6"5 x 260"), ultraviolet (1280-1880 A) spectrograph that sampled the coma parallel to the Sun-comet line from ~ 10~5 km sunward of the nucleus to ~2 x 10~5 km tailward with ~6'' (6000 km) spatial resolution. Two spectral images were obtained with the slit offset 20'' and 40'' from the nucleus in the direction perpendicular to the long axis of the slit. Spatial profiles and pro- duction rates for C, O, CO, and S are presented. Modeling of the spatial profiles of CO and C emissions indicate that photodissociation of the detected CO can account for all of the C I emissions observed. The brightnesses of the strong bands of the CO Fourth Positive system and the S I A1814 multiplet along near-nuclear lines of sight were dimimshed by self-absorption. A CO production rate of ~3 x 10~30 mol- ecules s- 1 is derived.