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Session 79 - White Dwarf Stars.
Display session, Wednesday, January 15
Metropolitan Ballroom,

[79.01] Distances to White Dwarf Stars from HIPPARCOS

J. Provencal, H. Shipman (U. Delaware), E. Hoeg (U. Kobenhavn), P. Thejll (Nordita)

We will present the results of a HIPPARCOS campaign to determine the distances to a number of white dwarf stars and we will discuss their implications. For bright stars, HIPPARCOS parallaxes have uncertainties that approach 1 milliarcsecond and thus they are considerably more accurate than earlier, ground-based parallaxes. Our most important finding is that the positions of important white dwarf stars in the mass-radius diagram, used to test our understanding of stellar degeneracy, have not changed appreciably. As a result the well known puzzles associated with 40 Eri B are still with us. The HIPPARCOS results indicate that the important binary V 471 Tau is a member of the Hyades cluster. The calibration star G 191-B2B is only an optical companion to the star G 191-B2A; these two objects are at different distances. The analysis of HIPPARCOS data has been supported by a grant from NASA.

Program listing for Wednesday