On 1997 March 30.14, we observed the EUV spectrum of the bright comet C/1995 O1 (Hale-Bopp) at the time of its perihelion, using our Extreme Ultraviolet Spectrograph sounding-rocket telescope/spectrometer. The spectra reveal the presence H Lyβ, O+, and, most notably, argon. Modeling of the retrieved Ar production rates indicates that comet Hale-Bopp is enriched in Ar relative to cosmogonic expectations. This in turn indicates that Hale-Bopp's deep interior has never been exposed to the 35-40 K temperatures necessary to deplete the comet's primordial argon supply.
The Astrophysical Journal
- Pub Date:
- December 2000
- Comets: General;
- Comets: Individual: Name: Hale-Bopp 1995 O1;
- Solar System: Formation;
- 9 pages, 2 figures. ApJ, 545, in press (2000)