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C.W. Ambruster, A. Brown, F.C. Fekel, E.F. Guinan, D. Fabian
We have completed simultaneous and /or contemporaneous multi-wavelength observations of six nearby Pleiades Moving Group K dwarfs with GHRS, EUVE, the IUE, ROSAT, the KPNO coude feed, and the Four College Automated Photometry Telescope (APT). Space motions and near-primordial lithium levels support a Pleiades age for these stars (70 Mys). The stars are all between K0 V and K2 V and are confirmed single (although one, HD 17925, has recently shown evidence of being a SB1). Stars of this mass are just arriving on the Zero-Age Main Sequence (ZAMS) in the Pleiades cluster. Both line and broadband surface fluxes will be presented, as well as rotation-activity relations for the major temperature regimes from the chromosphere to the corona. These stars provide the first opportunity to study not only the upper atmospheric properties of a cool ZAMS star, but also the response of the atmospheric parameters to rotation (8 hr < P rot < 6.9 d): since the stars have the same age, mass, and temperature, rotation is the only significant variable.
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