Ground-Based Observations of [OI]6300 Angstroms Emission from Io
Abstract
Since 1990, almost 1500 spectra of [O I] 6300 Angstroms emission from Io with good signal-to-noise have been obtained for all System III longitudes and all available Io orbital positions. When adjusted for long-term intensity variations, the data show a correlation with System III longitude, peaking where Io crosses the plasma torus centrifugal equator. We have also found a correlation between the flux and the Doppler width of the emission line. Included in this dataset are spectra of Io acquired during the October 14, 1997 HST/STIS FUV observations of Io's FUV neutral oxygen and sulfur emissions [Roesler et al. 1999]. The [O I] 6300 Angstroms emission increased in intensity simultaneously with the FUV O and S multiplets observed by STIS, but by a larger factor. The groundbased observations further show that, after the end of the HST observations, there was a sharp drop in intensity as Io crossed the torus centrifugal equator. \leavevmode \epsfxsize=0.8\hsize \epsfbox{416.eps}
- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #31
- Pub Date:
- September 1999
- Bibcode:
- 1999DPS....31.5812S