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White Dwarfs
NATO ASI Series Advanced Science Institutes Series
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Series C: Mathematical and Physical Sciences - Vol. 336
White Dwarfs
edited by
Gerard Vauclair Observatoire Midi-Pyrenees, Toulouse, Franca
and
Edward Sion Department of Astronomy, Villanova University, Villanova, Pennsylvania, U.SA
Springer-Science+Business Media, B.V.
Proceedings of the NATO Advanced Research Workshop Seventh European Workshop on White Dwarfs Toulouse, France September 3-5, 1990
Llbrary of Congress Cataloglng-In-Publicatlon Data
European Workshop on Whlte D~: arfs (7th : 1990 : Toulouse. France) Whlte dwarfs : proceedlngs l~ the NATD advanced research workshop
"Seventh European Workshop on Whlte Dwarfs · Toulouse. France. Septembre 3-5. 1990 / edltsd by Girard Vauclalr and Edward Sion.
p . cm . -- (NATD AS~ serles. Serles C. Mathematlcal and physlcal sclences ; voI. 336)
"Dedlcated to Evry Schatzman"--Pref. Inc 1 udes index. ISBN 978-94-010-5423-2 ISBN 978-94-011-3230-5 (eBook) DOI 10.1007/978-94-011-3230-5 1. Whlte dwarfs--Congresses. 1. Vauclalr. Girard. 1943-
II. Sion. Edward M. III . Schatzman. Evry L. IV. Tltle. V. Ser les : NATD ASI ser Ies. Serles C. Mathematical and physlcal sciences ; no. 109. OB843.W5E95 1990 523.8 ' e7--dc20 91-650
ISBN 978-94-010-5423-2
Printed on acid-free paper
AII Rights Reserved © 1991 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 1991 Softcover reprint of the hardcover 1 st edition 1991 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner.
Dedication
These Proceedings are dedicated to Evry Schatzman on the event of his seventieth birthday, in recognition of his contributions to research on white dwarf stars.
TABLE OF CONTENTS
Preface
Introduction
List of participants
1-PRE-WHITE DWARF EVOLUTION AND WHITE DWARF COOLING
New pre-white dwarf evolutionary tracks Blocker, T., Schon berner, D.
Influence of the phase diagram in the cooling of white dwarfs [sern, J., Garcia-Berro, E., Hernanz, M., Mochkovitch, R.
PG1159 stars and the PNN-white dwarf connection
xiii
xv
xvii
1
5
Barstow, M.A., Tweedy, R. W., Werner, K. 17
Analysis of the soft X-ray data from the central star of NGC 7293 Tweedy, R. W., Barstow, M.A. 29
Planetary Nebulae Nuclei with white dwarf spectra Napiwotzki, R., Schonberner, D. 39
Atmospheric parameters of subluminous B stars Saffer, R.A., Bergeron, P., Liebert, J., Koester, D. 53
White dwarf space densities and birth rates reconsidered Weidemann, V. 67
A spectroscopic determination of the mass distribution of DA white dwarfs Bergeron, P., Saffer, R.A., Liebert, J. 75
The age and formation of the Galaxy : clues from the white dwarf luminosity function Wood, M.A. 89
viii
Early results from the ROSAT Wide Field Camera Barstow, M.A, Abbey, A.F., Cole, RE., Denby, M., Page, C.G., Pankiewicz, G.S., Pounds, K.A., Pye, J.P., Sansom, A.E., Sims, M.R., Spragg, J.E., Watson, D.J., Wells, A.A., Willingale, R, Courtier, G.M., Gourlay, J.A., Harris, A. W., Kent, B.J., Reading, D.H., Richards, A.G., Swinyard, B.M., Wright, J.S., Goodall, C. V., Bentley, R.D., Breeveld, E.R., Guttridge, P.R, Huckle, H.E., McCalden, A.J., Bewick, A., Rochester, G.K., Sumner, T.J. 99
The stellar component of the Hamburg Schmidt Survey Heber, U., Jordan, S., Weidemann, V. 109
White dwarfs in the Hamburg Schmidt Survey Jordan, S., Heber, U., Weidemann, V. 121
2-ASTEROSEISMOLOGY OF WHITE DWARFS
Asteroseismology of white dwarf stars with the Whole Earth Telescope Winget, D.E. 129
A measurement of the evolutionary timescale of the cool white dwarf G1l7-B15A with WET Kepler, S.O., Kanaan, A., Winget, D.E., Natirer, RE., Bradley, P.A., Clemens, J.C., Kleinman, S.J., Claver, C.F., Provencal, J.L., Grauer, A.D., Fontaine, G., Bergeron, P., Wesemael, F., Wood, M.A., Vauclair, G., Marar, T.M.K., Seetha, S., Ashoka, B.N., Mazeh, T., Leibowitz, E., Dolez, N., Chevreton, M., Barstow, M.A., Sansom, A.E., Tweedy, RW., Hine, B.P., Solheim, J.-E., Emanuelsen, P.-I. 143
On the interpretation of the dP / dt measurement in G 117-B 15A Fontaine, G., Brassard, P., Wesemael, F., Kepler, S.O., Wood, M.A. 153
The boundaries of the ZZ Ceti instability strip Wesemael, F., Bergeron, P., Fontaine, G., Lamontagne, R 159
Long term variations in ZZ Cetis : G191-16 and HL Tau 76 Auvergne, M., Chevreton, M., Belmonte, J.A., Vauclair, G., Dolez, N., Goupil, M. J. 167
Predicting the white dwarf light curves Serre, T., Buchler, J.R, Goupil, M. J. 175
A wavelet analysis of the ZZ Ceti star G191 16 Goupil, M.J., Auvergne, M., Baglin, A.
An adiabatic survey for ZZ Ceti stars based on a finite element code Brassard, P., Fontaine, G., Pelletier, C., Wesemael, F.
A study of period change rates in post-AGB stars I. PG 1159-035 Stangbellini, L., Cox, A.N.
Nonadiabatic nonradial pulsations for DAV white dwarf stars Cox, A.N., Hollowell, D.E.
3-ATMOSPHERES AND ENVELOPES
NLTE Analysis offour PG1159 stars Werner, K., Heber, U., Hunger, K.
A search for trace amounts of hydrogen in DB stars Sbipman, H., Tbejll, P., Bbatia, 5., Liebert, J.
Abundances of trace heavy elements in hot DA white dwarfs Vennes, 5., Tbejll, P., Sbipman, H.L.
New results on radiative forces on iron in hot white dwarfs
ix
185
193
205
211
219
229
235
Cbayer, P., Fontaine, G., Wesemael, F. 249
The effective temperature of the DBV's, and the sensitivity of DB model atmospheres to input physics Tbejll, P., Vennes, 5., Sbipman, H.L. 257
The modified hydrostatic equilibrium equations for stratified high gravity stellar atmospheres Unglaub, K., Bues, I. 267
The DBAQ G35-26 Tbejll, P., MacDonald, J., Sbipman, H.L. 275
LP 790-29 : preliminary model atmospheres for this strongly polarized carbon white dwarf Bues, I. 285
x
Some effect of the UV radiation from white dwarfs on the accretion of interstellar hydrogen Verdon, C.P., McCrory, RL., Epstein, R, Van Horn, H.M., Savedoff, M.P. 295
Convection in white dwarfs : application of CM theory to helium envelope WDs Mazzitelli, I., D'Antona, F. 305
Abundances in cool DZA and DAZ white dwarfs: new results using laboratory damping constants Hammond, G. L., Sion, E.M., Kenyon, S.J., Aannestad, P.A. 317
Evidence for fractionated accretion of metals on cool white dwarfs Dupuis, J., Fontaine, G., Wesemael, F.
A new look at old friends: 40 Eri B and GD 323
333
Koester, D. 343
The Lyman Alpha line wing in hydrogen-rich white dwarf atmospheres Allard, N., Kielkopf, J. 353
Atmospheric parameters for DA white dwarfs in the vicinity of the ZZ Ceti instability strip Dolez, N., Vauclair, G., Koester, D. 361
Space Telescope observations of white dwarf stars Shipman, H.L. 369
4-WHITE DWARFS IN BIN ARIES
A deep spectroscopic survey of white dwarfs in common proper motion binaries Oswalt, T.D., Sion, E.M., Hintzen, P.M., Liebert, J. W.
Double degenerate common proper motion binaries Sion, E.M., Oswalt, T.D., Liebert, J., Hintzen, P.
Close binary white dwarfs Liebert, J., Bergeron, P., Saffer, RA.
379
395
409
xi
New results on cataclysmic variable white dwarfs Sion, E.M. 417
Whole Earth Telescope observations of the interacting white dwarf binary system AM CVn : first results Solheim, J.-E., Emanuelsen, P.-I., Vauclair, G., Dolez, N., Chevreton, M., Barstow, M., Sansom, A.E., Tweedy, R.W., Kepler, S.O., Kanaan, A., Fontaine, G., Bergeron, P., Grauer, A.D., Provencal, J.L., Winget, D.E., Nather, R.E., Bradley, P.A., Claver, C.F., Clemens, J.C., Kleinman, S.J., Hine, B.P., Marar, T.M.K., Seetha, S., Ashoka, B.N., Leibowitz, E.M., Mazeh, T. 431
ruE observations of V803 Cen in high and low states Una, A.M., Solheim, J.-E. 441
Whole Earth Telescope observations of PG 1346+082 Provencal, J.L., Winget, D.E., Nather, R.E., Clemens, J.C., Hine, B.P., Henry, G., Kepler, S.O., Vauclair, G., Chevreton, M., O'Donoghue, D., Warner, B., Grauer, D.A., Ferrario, L. 449
On the origin of LMXRBS : the ONEMG case Isern, J., Canal, R., Labay, J. 457
Index 465
PREFACE 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.
We are grateful for the help we received from our colleagues of the Scientific Organizing Committee: Francesca D'Antona, Jim Liebert and V. Weidemann. The practical support of Josiane Jobard is gratefully acknowledged.
On behalf of all the participants, we thank the Director of the NATO Scientific Affairs Division, the "Ministere de l'Education Nationale", the University Paul Sabatier of Toulouse and the Director of the Observatoire Midi-Pyrenees for granting financial support for a fruitful and stimulating Advanced Research Workshop.
Gerard Vauclair and Edward Sion
February, 1991
xiii
INTRODUCTION
Should I fIrst express the pleasure of being in Toulouse? My grand-mother has lived in Toulouse, her parents having a shop in the Place du Capitole where they sold clothes. From here came a very nice lullaby, used for rocking children, young children, to sleep:
Some some Beni Beni somme La some some es arribada A cavale su une cabra Rebendra du mamati A cavale su une pouli
This meeting, for me, is very moving. It is a remarkable meeting, with young people, and not so young ones, bringing to our attention an incredible amount of new results, new data, of a very high quality and high signal to noise ratio. Each talk brings to my mind the idea of a variety of physical problems, each one being more fascinating than the other and perhaps more difficult. Lots of people will have to tackle these problems during the coming years and to solve them.
But this meeting takes me back 47 years, when I was hiding in the Observatory of Haute Provence, near the small village of St Michell'Observatoire. Life was difficult, but nevertheless living was an absolute necessity, and after all, as I was studying in the observatory on the advice of one of my professors. I was there to continue to work as a physicist, which meant continuing to study and to learn, and, if possible, to produce. Two facts decided what happened. I read, probably in January 44, in a monthly magazine of popular science, Science et Vie, a paper explaining the theory of Hans Bethe of the thermonuclear origin of stellar light. It was fascinating, as it revealed to me the junction between astrophysics and physics. I ordered by mail a microfilm of the 1939 paper of Hans Bethe from the CNRS, and soon discovered in the Zeitschrift ffir Astrophysik a review paper of George Gamow which explained the whole thing, the crossing of the potential barrier and the effect of temperature.
Another fact came from an idea of Fehrenbach, who was then the vice-director of the Observatory. Having organized a seminar for the five scientists who were there, he asked me to give a review of part of the proceedings of the 1938 meeting in Paris on white dwarfs, Novae and Supernovae. Henry Norris Russell, in his introductory speech, tells that, trying to classify 40 Eri B, he discovered that it did not fall into the dwarf branch. He was desperate, having the feeling that his classification was falling apart. He discussed the question with Pickering, "his benefactor", who told him: "this is the kind of contradiction which is at the origin of great discoveries". This was in 1915. I spoke about white dwarfs. It turned out that I knew just enough statistical physics to understand the problem of the equation of state of a fully degenerate electron gas. I guess that I found in the supplement volume of the Handbuch der Astrophysik some information on the internal structure of white dwarfs. The book of Chandrasekhar (An Introduction of the Study of Stellar Structure) was not then available.
xv
xvi
Very soon I realized that the chemical composition of white dwarfs could not be the same as solar composition. The rate of thermonuclear reaction was incompatible with the luminosity of white dwarfs. The gravitational separation of hydrogen, floating at the surface of white dwarfs, came immediately to my mind and was the subject of my first publication on white dwarfs, in the Compte Rendus de I' Academie des Sciences, fall 1944.
I expressed my thanks to the astronomers who had hidden me, by accepting to act as a night assistant. But I swore also that, being a physicist, I would never become an astronomer. As James Bond said, "never say never again". However, it was not until the fall of 1946, when Daniel Barlier gave me the possibility of staying a few months with Bengt Stromgren in Copenhagen, that I decided to remain with the astronomers, but was still possessed by a love of physics.
When in 1955 or thereabouts, Hantz van de Hulbt, on behalf of North Holland, asked me to write a book on white dwarfs, I started immediately to work on the subject. At the time, Michael Seaton, the well known atomic physicist, was spending one year at the Institut d'Astrophysique in Paris, and I took that opportunity to ask him to correct my poor English, which he kindly did. But when I sent the manuscript to North Holland, they gave it for correction to an American scientist who was staying in The Netherlands and he again corrected the manuscript, including the corrections of Michael Seaton: I have not kept track of the linguistic fight that ensued, and this is too bad. I still kept in touch with the white dwarf problem without getting myself into the subject. Beginning in 1962, A. Baglin gave a complete description of non-zero temperature WD, including the general relativity effects, around the maximum mass of WD, opening the way to the description of gravitational collapse and SN production; twelve years later I began this work with Ramon Canal on the problem of non-explosive collapse, and at the time of the 1978 meeting on dense matter, brought Robert Mochkovitch in on this same subject. I remained attracted by the new physical problems which were arising.
A question which I clearly met for the first time some 40 years ago, was the well known question: how useful is what I am doing? Considering the energy production of white dwarfs, even if it drove me to the problem of the effect of pressure on the potential barrier in 1947, did not seem to me to have any application of any kind. It took me many many years to realize that this was a wrong question. The level of culture and the development of scientific research, always leads to unpredictable discoveries and, nonetheless, unpredictable applications. To carry on scientific work, having in mind the aim of rmding useful applications, is not doing science. The sentence itself is self-contradictory and we have to make understood to the layman as well as to the politicians, that such a statement is meaningless.
We are enjoying this evening, with a slight change in the weather. The political weather has been changing during the last weeks. It is impossible for me, when this meeting, so well organized and bringing back memories of events of the last 50 years, not to think of the present threat to our world. Let us hope that international law and human rights will prevail in this crisis and be respected with devotion by all nations of the world.
Evry Schatzman
LIST OF PARTICIPANTS
Numbers in parentheses refer to the group photography
Dr. N. ALLARD (4)
Dr. M. AUVERGNE (36)
Dr. M.A. BARSTOW (12)
Dr. J.-A. BELMONTE (6)
Dr. P. BERGERON (35)
Dr. P. BRASSARD (8)
Dr. I. BUES (23)
Mrs. A. BRUVOLD (38)
Dr. G. CHABRIER (37)
Dr. P. CHAYER (9)
Dr. F. D'ANTONA (27)
Dr. N. DOLEZ (13)
Dr. J. DUPUIS (11)
Dr. G. FONTAINE (10)
Dr. M.-J. GOUPIL (24)
LAM, Observatoire de Meudon 92195 Meudon Principal Cedex, France DASGAL, Observatoire de Paris-Meudon 92195 Meudon Principal Cedex, France X-Ray Astronomy Group, Physics Dpt. University of Leicester, University Road Leicester, LEI 7RH, U.K. Instituto de Astrofisica de Canarias 38200 La Laguna, Tenerife, Spain Steward Observatory, The University of Arizona Tucson, Arizona 85721, U.S.A. Departement de Physique, Universite de Montreal P.O. Box 6128, succ. "A" Montreal, PQ H3C 3J7 Canada Dr. Remeis-Sternwarte Bamberg Astron. Institut der Universitat Erlanger-Niirnberg Sternwartstrasse 7 D 8600 Bamberg - F.R.G. University of Tromso, Institute of Mathematical and Physical Sciences, N-9000 Tromso, Norway Laboratoire de Physique, ENS Lyon 46, Allee d'Italie 69364, Lyon Cedex 07, France Departement de Physique, Universite de Montreal P.O. Box 6128, succ. "A" Montreal, PQ H3C 3J7 Canada Osservatorio Astronomico, 00040 Monte Porzio Rome, Italy Observatoire Midi-Pyrenees 14, avenue Edouard Belin 31400 Toulouse, France Department of Physics & Astronomy Wilder Lab., Dartmouth College Hanover, N.H. 03755, U.S.A. Departement de Physique, Universite de Montreal P.O. Box 6128, succ. "A" Montreal PQ H3C 3J7 Canada DASGAL, Observatoire de Paris Meudon 92195 Meudon Principal Cedex, France
xvii
xviii
Dr. G. HAMMOND (19)
Dr. U. HEBER (14)
Dr. J.B. HOLBERG (20)
Dr. J. ISERN (5)
Dr. S. JORDAN (17)
Dr. S.O. KEPLER (16)
Dr. D. KOESTER (40)
Dr. J. LIEBERT (28)
Dr. T. D. OSWALT (42)
Dr. C. A. OXBORROW (25)
Dr. J. PROVENCAL (22)
Dr. E. POULIN (45)
Dr. R. SAFFER (34)
Dr. E. SCHATZMAN (3)
Dr. D. SCHONBERNER (18)
Dr. T. SERRE (22)
Dept. of Mathematics (Astro. Prog.) University of South Florida, Tampa, FL 33620, U.S.A. Institut fUr Theoretische Physik und Sternwarte der Universitat, Olshausenstrasse 40 0-2300 Kiel, 1 F.R.G. Lunar and Planetary Laboratory-West 9th Floor, Gould-Simpson Building University of Arizona, Tucson, AZ 85721, U.S.A. Centre d'Estudis A van!,tats de Blanes Cami de Santa Barbara, 17300 Blanes (Girona) Spain Institut fur Theoretische Physik und Sternwarte der Universitat, Olshausenstrasse 2300 Kiel, F.R.G. Departement de Physique, Universite de MontPeal P.O. Box 6128, succ. "A" Montreal PQ H3C 3J7 Canada Dept of Physics and Astronomy 266 Nicholson Hall, Louisiana State Univ. Baton-Rouge, LA 70803-4001, U.S.A. Steward Observatory, The University of Arizona Tucson, Arizona 85721, U.S.A. Dept. Physics & Space Sciences Florida Institute of Technology Melbourne, FL 32901, U.S.A. Nordita, Blegdamsvej 17 OK -2100, Kobenhavno, Denmark Department of Astronomy, University of Texas Austin, TX 78712, U.S.A. Departement de Physique, Universite de Montreal P.O. Box 6128, Succ A Montreal P.Q. H3C 3J7 Canada Steward Observatory, University of Arizona Tucson, AZ 85721, U.s.A. DASGAL, Observatoire de Meudon 92195 Meudon Principal Cedex, France Institut fur Theoretishe Physik und Sternwarte der Universitat, Olshausenstrasse D -2300 Kiel, F.R. G. DASGAL, Observatoire de Paris Meudon 92195 Meudon Principal Cedex, France
Dr. H. SHIPMAN (31)
Dr. E. SION (7)
Dr. J.E. SOLHEIM (41)
Dr. L. STANGHELLINI (29)
Dr. P. THEJLL (46)
Dr. R. TWEEDY (1)
Dr. K. UNGLAUB (43)
Dr. A. M. ULLA (30)
Dr. H. Van HORN (15)
Dr. G. VAUCLAIR (2)
Dr. S. VENNES (44)
Dr. V. WEIDEMANN (26)
Dr. F. WESEMAEL (39)
Dr. D. E. WINGET (32)
Dr. M. WOOD (33)
Physics Department, University of Delaware Sharp Lab., Newark, DE 19716, U.S.A. Dept. of Astronomy and Astrophysics Villanova University, Villanova, Pennsylvania 19085, U.S.A.
xix
Institute of Mathematical and Physical Sciences University of Tromso, P.O. Box 953, N-9001 Tromso, Norway Osservatorio Astronomico di Bologna Via Zamboni 33, 40146 BOLOGNA, Italy Nordita, Blegdamsvej 17 DK-2100, Kobenhavno, Denmark Department of Physics, University of Leicester University Road, Leicester LEI 7RH, U.K. Dr. Remeis-Sternwarte Bamberg Astronomisches Inst. der Universitat Erlangen-Niirnberg, D-8600 Bamberg, F.R.G. Instituto de Astrofisica de Canarias lAC, 38200 La Laguna, Tenerife, Spain Dept. of Physics and Astronomy University of Rochester, Rochester, NY 14627 U.S.A. Observatoire Midi-Pyrenees 14, avenue E. Belin, 31400 Toulouse, France Physics Department, University of Delaware Sharp Lab. Newark, DE 19716, U.S.A. Institut fiir Theoretische Physik und Sternwarte der Universitat Olshausenstrasse 2300 Kiel, F.R.G. Departement de Physique, Universite de Montreal P.O. Box 6128, Succ. A Montreal P.Q. H3C 3J7 CANADA Department of Astronomy, Univeristy of Texas Austin, TX 78712, U.S.A. Departement de Physique, Universite de Montreal P.O. Box 6128, succ. "A" Montreal, PQ H3C 3J7 Canada
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