Outflow Velocities of Dust as a Function of Time in the Coma of Comet 1P/Halley
Abstract
We are presenting the measured sky-plane projected dust outflow velocity in the coma of Comet 1P/Halley. Based on dust features in 72 images taken from December 1985 to May 1986, it was possible to identify 21 unambiguous features. The images were obtained from the Small Bodies Node of the NASA Planetary Data System (PDS-SBN). They were originally taken from many different observatories during the International Halley Watch (IHW) initiative. The results for the projected outflow velocities will be presented as functions of both the heliocentric distance and the cometocentric distance. We will show that there is a factor of two difference between the inbound and outbound mean projected outflow velocities of Comet 1P/Halley. For pre-perihelion, the average of the mean projected outflow velocity is approximately 0.09 km/s with a range of 0.04 to 0.17 km/s. In the post-perihelion time frame, the average of the mean projected outflow velocity is approximately 0.23 km/s with a range of 0.11 to 0.48 km/s. There is clear evidence for acceleration of dust particles ejected from the nucleus as a function of cometocentric distance at each heliocentric distance. However, for a small fraction of dust features, we observe the opposite effect probably due to projection effects. This investigation is part of a broader study that will investigate the coma morphology and the lightcurve data to successfully develop a model to provide a self-consistent picture for the rotation and the activity of the comet.This work is supported by NASA Planetary Atmospheres grant NNX11AD85G.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #46
- Pub Date:
- November 2014
- Bibcode:
- 2014DPS....4620927L