Extreme Non-LTE H2 in Comets C/2000 WM1 (LINEAR) and C/2001 A2 (LINEAR)
Abstract
Rotationally resolved molecular hydrogen transitions originating from excitation of highly excited rovibrational levels of the X 1Σ+g state have been systematically identified for the first time in the Far Ultraviolet Spectroscopic Explorer (FUSE) observation of comets C/2000 WM1 (LINEAR) and C/2001 A2 (LINEAR). Spectral assignments for the observed lines of H2 and other atomic and molecular species are given. All observed H2 transitions belong to the Lyman (B 1Σ+u-X 1Σ+g) and Werner (C 1Πu-X 1Σ+g) band systems. Solar Lyα fluorescence excitation of highly rovibrationally excited H2 X 1Σ+g is found to be almost solely responsible for the observed H 2 emission. Resonant excitation of H2 by Lyβ and other solar lines is very limited.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- April 2007
- DOI:
- 10.1086/511686
- Bibcode:
- 2007ApJS..169..458L
- Keywords:
-
- Comets: General;
- Comets: Individual: Alphanumeric: C/2000 WM1;
- Comets: Individual: Alphanumeric: C/2001 A2;
- Molecular Processes;
- Ultraviolet: Solar System