White Dwarfs

The European Workshop on White Dwarfs was initiated by Prof. V. Weidemann, with the first meeting organized in Kiel (FRG) in 1974. Almost every two years, an increasing number of astronomers met to share their results and projects in the subsequent workshops: Frascati (1976), Tel Aviv (1978), Paris (1981), Kiel (1984), Frascati (1986). In the mean time, two major IAU colloquia (No. 53 in Rochester, NY, 1979; and No. 114 in Hanover, NH, 1988) emphasized the importance of these stars for our understanding of stellar evolution. The informal organization of the white dwarf community has been the starting point for large cooperative projects of which the Hubble Space Telescope "White Dwarf Consortium" and the "Whole Earth Telescope" are the most spectacular examples. But many other successful collaborations have also been born during the very exciting discussions conducted in the last 16 years on the occasion of our regular meetings. The 7th European Workshop on White Dwarfs took place the year of the seventieth birthday of Prof. Evry Schatzman, whose pioneering work has been the inspiration for many of the new ideas in the white dwarf community. The Scientific Organizing Committee has agreed to dedicate the workshop to him on this occasion. We are pleased to publish as an introduction to the workshop, the text of the talk delivered by Prof. Schatzman at the workshop's banquet.

Inhalt

1-Pre-White Dwarf Evolution and White Dwarf Cooling.- New pre-white dwarf evolutionary tracks.- Influence of the phase diagram in the cooling of white dwarfs.- PG1159 stars and the PNN-white dwarf connection.- Analysis of the soft X-ray data from the central star of NGC 7293.- Planetary Nebulae Nuclei with white dwarf spectra.- Atmospheric parameters of subluminous B stars.- White dwarf space densities and birth rates reconsidered.- A spectroscopic determination of the mass distribution of DA white dwarfs.- The age and formation of the Galaxy : clues from the white dwarf luminosity function.- Early results from the ROSAT Wide Field Camera.- The stellar component of the Hamburg Schmidt Survey.- White dwarfs in the Hamburg Schmidt Survey.- 2-Asteroseismology of White Dwarfs.- Asteroseismology of white dwarf stars with the Whole Earth Telescope.- A measurement of the evolutionary timescale of the cool white dwarf G117-B15A with WET.- On the interpretation of the dP/dt measurement in G117-B15A.- The boundaries of the ZZ Ceti instability strip.- Long term variations in ZZ Cetis : G191-16 and HL Tau 76.- Predicting the white dwarf light curves.- A wavelet analysis of the ZZ Ceti star G191 16.- An adiabatic survey for ZZ Ceti stars based on a finite element code.- A study of period change rates in post-AGB stars I. PG 1159-035.- Nonadiabatic nonradial pulsations for DAV white dwarf stars.- 3-Atmospheres and Envelopes.- NLTE Analysis of four PG1159 stars.- A search for trace amounts of hydrogen in DB stars.- Abundances of trace heavy elements in hot DA white dwarfs.- New results on radiative forces on iron in hot white dwarfs.- The effective temperature of the DBV's, and the sensitivity of DB model atmospheres to input physics.- The modified hydrostatic equilibrium equations for stratified high gravity stellar atmospheres.- The DBAQ G35-26.- LP 790-29 : preliminary model atmospheres for this strongly polarized carbon white dwarf.- Some effect of the UV radiation from white dwarfs on the accretion of interstellar hydrogen.- Convection in white dwarfs : application of CM theory to helium envelope WDs.- Abundances in cool DZA and DAZ white dwarfs : new results using laboratory damping constants.- Evidence for fractionated accretion of metals on cool white dwarfs.- A new look at old friends : 40 Eri B and GD 323.- The Lyman Alpha line wing in hydrogen-rich white dwarf atmospheres.- Atmospheric parameters for DA white dwarfs in the vicinity of the ZZ Ceti instability strip.- Space Telescope observations of white dwarf stars.- 4-White Dwarfs in Binaries.- A deep spectroscopic survey of white dwarfs in common proper motion binaries.- Double degenerate common proper motion binaries.- Close binary white dwarfs.- New results on cataclysmic variable white dwarfs.- Whole Earth Telescope observations of the interacting white dwarf binary system AM CVn : first results.- IUE observations of V803 Cen in high and low states.- Whole Earth Telescope observations of PG1346+082.- On the origin of LMXRBS : the ONEMG case.