Recent Science Highlights

22 December 1994

• Schmitt, Drake, Stern and Haisch have determined the coronal density of the nearby star alpha Canis Minoris (CMi), using ratios from detected iron spectral lines of different ionization stages (ranging from FeIX to FeXIV). All the studied line ratios yield densities consistent with those found in solar active regions. This implies that the corona of alpha CMi is, presumably, structured in a similar manner as to that of the Sun and, furthermore, the coronal filling factor is estimated to be about 20%.
• Drake, Laming and Widing have analyzed spectral lines due to the elements Ne, S, Ar, Fe, and Si in the EUVE spectrum of the alpha Centaurus AB system. The results indicate a significant enhancement of the species with low first ionization potentials (FIPs) -- Fe and Si -- in the corona with respect to their photospheric abundances. A similar situation exists in the solar corona (the "FIP Effect"). This result is the first detection of the FIP effect in a stellar corona.
• Monsignori-Fossi, Landini, Fruscione, and Dupuis have studied the EUVE spectra of the star EQ Pegasi which was detected at all EUVE wavelengths and was successfully monitored by the Deep Survey photometer. They identified the main features observed in the spectra and concluded that a number of lines are produced by high ionization stages of iron. Evidence of activity modulation during the observation is present in both photometric and spectroscopic data.