Extreme Ultraviolet Emission from Late-Type Stars: Early Results from EUVE

We present selected early results on the extreme ultraviolet (EUV) emission from late-type stars obtained with the Extreme Ultraviolet Explorer (EUVE) satellite. EUVE is performing a sensitive all-sky survey in four bandpasses across the EUV centered at roughly 100 Angstroms, 200 Angstroms, 450 Angstroms and 600 Angstroms, plus a deep survey of a portion of the sky in the 100 Angstroms and 200 Angstroms bands. In this paper we present measured EUV fluxes in several bandpasses for a sample of nearby late-type stars from the all-sky survey and in-orbit calibration observations, including alpha Cen, Prox Cen, HR 6094, xi Boo, epsilon Eri and alpha CMi. Constraints on the amounts of emitting material between a few times 10(5) and 10(7) K in the upper atmospheres and coronae of these stars are derived. We also examine the time variability and flaring activity in the EUV for these objects. Results for a number of other cool stars observed to date will also be presented, including some correlations with X-ray and ultraviolet measurements indicative of coronal and transition region emission. This work has been supported by NASA contracts NAS5-30180 and NAS5-29298.