Evidence for pyroxene dust grains in C/2001 C2 sungrazing comet
Abstract
In this paper we analyze SOHO/UVCS data of the sungrazing comet C/2001 C2, a member of the Kreutz family, observed on February 7, 2001, at the heliocentric distances of 4.94 and 3.44 solar radii. As confirmed also by LASCO/C3 images, this comet splits in a main nucleus and a fragment which have been identified also in our UV data. A study of the cometary Hydrogen Lyα emission from these two objects showed a different behaviour: the Lyα signal from the fragment decays exponentially with time, as expected in terms of the H_2O outgassing rate and of the charge transfer between the coronal protons and atoms created by the photodissociation of water. On the contrary the signal from the main object consists of an exponentially decaying term plus a constant background. This secondary component has been ascribed to the sublimation of pyroxene dust grains, whose end products neutralize coronal protons via charge exchange processes. Hence, the two fragments have a different composition; differences throughout the comet body may have been the primary cause for the comet fragmentation.
- Publication:
-
35th COSPAR Scientific Assembly
- Pub Date:
- 2004
- Bibcode:
- 2004cosp...35.3526B