SUMMARY OF PROPOSAL 42016 DR. STEPHEN M. WHITE UNIVERSITY OF MARYLAND MD USA 20742 COLLEGE PARK E-mail: WHITE@ASTRO.UMD.EDU Tel: (301) 405 1547 Fax: (301) 314 9067 Medium: 2GB8MM Subject: STARS Title: THE NATURE OF THE X-RAY SOURCE IN THE PRECATACLYSMIC BINARY V471 TAURI Abstract: V471 Tauri is a ``touchstone'' system for a wide range of important areas of stellar research, including stellar evolution, cataclysmic variables, open clusters, binary stars, stellar activity, and red and white dwarf physics. It is one of the brightest X-ray sources in the Hyades. Following on our successful EUVE/optical/radio campaign, we propose the first ASCA observation of this star in order to study the distribution of heated plasma in the V471 Tau system and to look for evidence for the origin of the soft X-rays: stellar activity, or interaction between the K dwarf and the white dwarf. Co-Is: 1 JEREMY LIM IAA, ACAD. SINICA TAIWAN (No Co-I contact data) 2 SCOTT L. CULLY SSL, U.C.-BERKELEY USA Target Name PRI RA Dec Time TC Off GIS SIS_Cts Obs ------------------- --- -------- -------- ---- -- --- --- ------- --- V471 TAURI 0 57.6017 17.2467 50 N N P 0.27000 1