Near-infrared images of comet Hale-Bopp (C/1995 O1) were obtained from NICMOS/HST on UT August 27-28, 1997, when the comet emerged from the 50 degree solar elongation limit at 2.99 AU from Earth. Diffraction-limited images were obtained with camera 2 filters centered at 1.87, 1.90, 2.04 and 2.22 μm with ~0.2″ resolution (0.076″/pixel; 165 km/pixel). Over the 1.7-hour baseline of observation, a recent (<7 hours) outburst is seen in the form of an expanding spiral arm with a projected expansion velocity of ~80 m/s. Other asymmetric features include a jet emanating from the nucleus and several static linear features. Comparisons of the flux distribution in the 2.04 and 2.22 μm filters indicate that the region near the nucleus exhibits a slight, ~3%, water ice absorption.
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science