Simultaneous/Contemporaneous EUVE, ASCA, IUE, VLA & AT Observations of the RS CVn binary HR1099 in August 1994

We present results from a set of coordinated multiwavelength observations of the RS CVn binary HR1099 (V711 Tau; G5 IV + K1 IV) obtained over the period 1994 August 23-28. These data include simultaneous EUV, X-ray, and UV spectroscopy from EUVE, ASCA, and IUE plus radio continuum observations from the VLA and AT arrays. The complete observational dataset covers almost two complete binary orbits (P_orb = 2.838 days). The data from all spectral regions show intermittent flaring superimposed on a slowly varying ``quiescent'' emission. The 40 ksec ASCA observation shows a ``flare outburst'' spanning 15 ksec and producing a factor of 2 increase in both SIS and GIS count rate. Spectral evolution is seen within the flare. The 100 ksec EUVE observation extends over 4 days and shows two major flare outbursts and other lower level variations. These EUV coronal outbursts correspond to times of enhanced UV transition region emission; however the maxima in the UV fluxes occur at the start of each outburst and the EUV and UV peaks are separated by several hours. Detailed analyses of the observations in each spectral region will be presented and the differing behavior seen compared. This work is supported by NASA grants NAG5-2259, NAG5-2530, and NAG5-985 to the University of Colorado.