The Impact of Long-Term Monitoring on Variable Star Research: Astrophysics, Instrumentation, Data Handling, Archiving

470 Pages·1994·16.35 MB·English

by  C. Sterken (auth.)

The Impact of Long-Term Monitorin g
on Variable Star Researc h
NATO ASI Series
Advanced Science Institutes Series
A Series presenting the results of activities sponsored by the NATO Science Committee,
which aims at the dissemination of advanced scientific and technological knowledge,
with a view to strengthening links between scientific communities.
The Series is published by an international board of publishers in conjunction with the
NATO Scientific Affairs Division
A Lif e Sciences Plenum Publishing Corporation
B Physic s London and New York
C Mathematica l Kluwer Academic Publishers
and Physical Sciences Dordrecht, Boston and London
D Behavioura l and Social Sciences
E Applie d Sciences
F Compute r and Systems Sciences Springer-Verlag
G Ecologica l Sciences Berlin, Heidelberg, New York, London,
H Cel l Biology Paris and Tokyo
I Globa l Environmental Change
NATO-PCO-DATA BASE
The electronic index to the NATO ASI Series provides full bibliographical references
(with keywords and/or abstracts) to more than 30000 contributions from international
scientists published in all sections of the NATO ASI Series.
Access to the NATO-PCO-DATA BASE is possible in two ways:
- vi a online FILE 128 (NATO-PCO-DATA BASE) hosted by ESRIN,
Via Galileo Galilei, I-00044 Frascati, Italy.
- vi a CD-ROM "NATO-PCO-DATA BASE" with user-friendly retrieval software in
English, French and German (© WTV GmbH and DATAWARE Technologies Inc.
1989).
The CD-ROM can be ordered through any member of the Board of Publishers or
through NATO-PCO, Overijse, Belgium.
Series C: Mathematical and Physical Sciences - Vol. 436
The Impact of Long-Term
Monitoring on Variable
Star Research
Astrophysics, Instrumentation,
Data Handling, Archiving
edited by
Christiaan Sterken
Belgian Fund for Scientific Research (NFWO)
University of Brussels,
Brussels, Belgium
and
Mart de Groot
Armagh Observatory,
College Hill,
Armagh, Northern Ireland
w
SPRINGER-SCIENCE+BUSINESS MEDIA , B.V .
Proceedings of the NATO Advanced Research Workshop on
The Impact of Long-Term Monitoring on Variable Star Research:
Astrophysics, Instrumentation, Data Handling, Archiving
Ghent, Belgium
November 15-18, 1993
A C.I.P. Catalogue record for this book is available from the Library of Congress.
ISBN 978-94-010-4507-0 ISBN 978-94-011-1164-5 (eBook)
DOI 10.1007/978-94-011-1164-5
Printed on acid-free paper
All Rights Reserved
© 199 4 Springer Science+Business Media Dordrech t
Originally published by Kluwer Academic Publishers in 1994
Softcover reprint of the hardcover 1st edition 1994
No par t o f th e materia l protecte d b y this copyrigh t notic e ma y b e reproduce d o r
utilized i n an y for m o r b y an y means , electroni c o r mechanical , includin g photo -
copying, recording or by any information storage and retrieval system, without written
permission from the copyright owner.
TABLE OF CONTENTS
page
Preface ix
The Scientific Organising Committee xi
Conference Photograph xii
List of Participants xv
SESSION I. OBSERVATIONS: EMISSION-LINE STARS
- Chair: C. Waelkens
Long-Term Photometry of Variables: The story of HD 160529
C. Sterken 1
New astrophysical insights based on historical and modern data of
TJ Carinae 1935-1992
A.M. van Genderen, M. de Groot, P.S. The 19
Evidence for circumstellar disks around variable Herbig Ae/Be stars
from long-term photometry
P.S. The 31
Ten years of monitoring southern Be stars: Results from the ESO
LTPV project
N. Vogt, R. Mennickent, C. Sterken 41
SESSION I: continued - Chair: M. Breger
Long-term monitoring of the complex variations of Be stars
P. Harmanec 55
DISCUSSION No.1: Be stars 73
Long-term radio monitoring of Wolf-Rayet stars
with non-thermal emission
K.A. van der Hucht, P.M. Williams, T.A. Th. Spoelstra, J.P. Swaanenvelt 75
vi
Long-term infrared photometry of WC stars making circumstellar dust
P.M. Williams, K.A van der Hucht 85
Photometric monitoring of Wolf-Rayet stars: Stromgren uvby
and narrow-band photometry
E. Gosset, G. Rauw, J. Man/raid, J.-M. Vreux, C. Sterken 101
Variability of Wolf-Rayet stars: constraints on the properties of hot-star winds
A.F.J. Moffat 117
DISCUSSION No.2: Wolf-Rayet stars 141
SESSION II: OBSERVATIONS: BINARIES
AND PULSATING STARS - Chair: A. Moffat
Long-term variability of Barium and S stars
A. Jorissen 143
A long-term photometric campaign approach
to the study of symbiotic variables
L. Hric, D. Chochol, R. Komiik, A. Skopal, Z. Urban, P. Niarchos 163
Long-term light and period variations of some contact binaries
O. Demircan 177
Long-term monitoring of cyclic frequency variability in roAp stars at the
Sutherland station of the South African Astronomical Observatory
D. W. Kurtz, P. Martinez 185
SESSION II: continued - Chair: D. Kurtz
Long-term photometry of Ap stars
H. Hensberge 197
DISCUSSION No.3: Binaries and Ap stars 209
Problems and perspectives of long-term observations of Population I
and II Cepheids, RR Lyrae-type and other luminous pulsating stars
L. Szabados 213
The story of AI Velorum: A review
Th. Walraven, J.H. Walraven 229
Long-term monitoring of the extreme galactic Cepheids V810 Centauri
and V473 Lyrae
G. Burki 247
Hot pulsating stars in the Geneva system
C. Waelkens 255
DISCUSSION No.4: Pulsating stars 267
vii
SESSION III: MISCELLANEOUS ASPECTS OF
SPECTROGRAPHIC, SPECTROMETRIC AND PHOTOGRAPHIC
MONITORING - Chair: L. Szabados
Instrumental effects in stellar spectroscopy
D. Dravins 269
Investigation of Luminous Blue Variables of the Magellanic Clouds
during the past decade with LTPV, CASPEC and IUE
B. Wolf 291
Fiber-linked echelle spectrographs: the ideal tool for high-resolution
spectroscopic long-term monitoring
H. Mandel 303
Spectroscopic monitoring of OBA stars
O. Stahl, A. Kaufer 311
Multichannel multicolour photometry: Experiences from a long-term
monitoring campaign
K.H. Mantei, H. Barwig 329
DISCUSSION No.5: Spectroscopy 345
SESSION III: continued - Chair: P. Harmanec
Long-term optical monitoring of Gamma-ray burst sources
H. Pedersen 347
Archives of variable-star observations - History, use and prospects
H. W. Duerbeck 353
Computerised very-long-term monitoring of variables and the
Sonneberg Plate Archive
P. Kroll 365
DISCUSSION No.6: Photographic photometry 375
Lessons learned from 30 years of long-term variable-star photometry
D.S. Hall 379
SESSION IV: PHOTOMETRIC SYSTEMS, ARCHIVING,
DATA ANALYSIS - Chair: B. Wolf
Long-term aspects of multi-site campaigns
M. Breger 393
Geneva photometry and its homogeneity
N. Cramer 405
viii
Photometric monitoring: Accuracy, homogeneity and precision
in existing long-term projects
A. T. Young 421
Stromgren photometry, galactic research, and variable stars
E.H. Olsen 437
GENERAL DISCUSSION - Chair: C. Sterken 445
RESOLUTION 449
INDEX 451
PREFACE
The theme of this workshop was about the kind of variable-star research that
can only be succesfull if carried out in long-term monitoring (LT M) mode-that is,
with observations covering a time span of a decade or longer. The scientific topics
discussed included photometric and spectrographic observations of importance for
the understanding of the physics of emission-line stars (Luminous Blue Variables,
Herbig Ae/Be stars, Be and WR stars), binaries, and pulsating stars (13 Cephei
stars, 8 Scuti stars, Ap stars, mid-B variables, Cepheids, RR Lyrae variables).
Besides reports based on the analysis of data collected in the wavelength range
of visible light (photographic, photoelectric and spectrometric data, as well as vi
sual estimates), conclusions based on infrared and on radio measurements were
presented.
The design and history of well-known photometric systems, viz. the Geneva
and the Stromgren photometric systems, is described in a couple of papers. Special
emphasis was placed on novel designs of stable photometers and spectrometers with
high spectral fidelity, and their application to LTM .
Several talks focused attention on secular changes of periods, and on period
determination techniques for data collected on a very long-term basis.
Detailed discussions on pittfalls in observational work with relation to accu
racy, homogeneity and precision of the data, with emphasis on the prevention of
systematic error, took place.
Though the reporting of novel results was an important ingredient of the meet
ing, the workshop was not organised to communicate new findings only, but also
to discuss discoveries on the background of LTM as a method to obtain those new
results. The contents of 8 Discussion Sessions-which are integrally described in
these Proceedings-not only refer to the talks and lectures, but also cover more
general areas, such as extinction monitoring, the problem of archiving of astro
nomical data, service observing, the role long-term monitoring plays in graduate
teaching and thesis supervision, the interplay between the large observational effort
and theory, the contribution of LTM to new knowledge of fundamental data (i.e.
masses, radii), and the increasing decommissioning oftelescopes of modest aperture
used for long-term monitoring.
The meeting valued the great wealth of information collected by many work-
ix
x
ing groups involved in LTM campaigns covering a wide variety of astrophysical
aspects, and realized the potential of long-term observations achievable with small
instruments for the identification of scientific problems through complementary ap
proaches with the new generation of very-large telescopes.
The Workshop's conclusion was the recognition of the fundamental significance
of long-term observations for solving many important problems in astrophysics,
and the unequaled value of extended observing runs with small telescopes for the
education of young astronomers in order to teach them how to secure-over many
years-observational data of high quality. The participants of the Workshop have
unanimously adopted a resolution in support of the continuation of the operation of
those observing facilities that are involved with long-term monitoring programmes.
The Workshop was supported by a generous grant from NATO, and by ad
ditional grants from the Belgian Fund for Scientific Research (NFWO) and the
University of Brussels (VUB).
Acknowledgement
The Editors express their gratitude to the NATO Science Committee for allocat
ing a NATO-ARW grant, and to the other members of the Scientific Organising
Committee for their most valuable support during the preparation of the scientific
programme of the meeting. One of us (MdG) acknowledges financial support from
the Department of Education in Northern Ireland through an annual grant-in-aid
for the operation of the Armagh Observatory. Miss Aileen Brannigan provided
invaluable assistance in the editing of the many, not always quite camera-ready,
manuscripts.