Problems of Calibration of Absolute Magnitudes and Temperature of Stars: Held in Geneva, Switzerland, September 12–15, 1972

300 Pages·1973·7.84 MB·English

by  P. Van De Kamp (auth.)

PROBLEMS OF CALIBRATION OF
ABSOLUTE MAGNITUDES AND TEMPERATURE
OF STARS
INTERNATIONAL ASTRONOMICAL UNION
UNION ASTRONOMIQUE INTERNATIONALE
SYMPOSIUM No. 54
HELD IN GENEVA, SWITZERLAND, SEPTEMBER 12-15, 1972
PROBLEMS OF CALIBRATION OF
ABSOLUTE MAGNITUDES
AND TEMPERATURE OF STARS
EDITED BY
B. HAUCK
Institut d' astronomie de l' Universite de Lausanne
et Observatoire de Geneve, Szitzerland
AND
B. E. WESTERLUND
ESO, Santiago, Chile
D. REIDEL PUBLISHING COMPANY
DORDRECHT-HOLLAND / BOSTON-U.S.A.
1973
Published on behalf of
the International Astronomical Union
by
D. Reidel Publishing Company, P. O. Box 17, Dordrecht, Holland
All Rights Reserved
Copyright © 1973 by the International Astronomical Union
Sold and distributed in the U.S.A., Canada, and Mexico
by D. Reidel Publishing Company, Inc.
306 Dartmouth Street, Boston,
Mass. 02116, U.S.A.
Library of Congress Catalog Card Number 73-83562
ISBN-13: 978-90-277-0372-9 e-ISBN- 13: 978-94-010-2645-1
DOl: 10.1007/978-94-010-2645-1
No part of this book may be reproduced in any form, by print, photoprint, microfilm,
or any other means, without written permission from the publisher
T ABLE OF CONTENTS
PREFACE IX
THE ORGANIZING COMMITTEES x
PART II ABSOLUTE MAGNITUDES FROM
TRIGONOMETRIC AND STATISTICAL PARALLAXES
P. V AN DE KAMP I Absolute Magnitudes from Trigonometric and Statistical
Parallaxes (Survey Lecture) 3
w. J. LUYTEN I The Determination of Absolute Magnitudes from Proper Motions 11
s. L. LIPPINCOTT I Note on Absolute Magnitudes in the Red and Infrared of
Late M-Type Dwarfs 18
A. HECK I Magnitude absolue moyenne des RR Lyrae 21
w. F. VAN ALTENA I A Program to Determine an Accurate Trigonometric
Parallax for the Hyades Cluster 23
PART II I ABSOLUTE MAGNITUDES FROM
GALACTIC CLUSTERS AND ASSOCIATIONS
P. R. DEMARQUE I Absolute Magnitudes from Galactic Cluster and Associa
tions (Survey Lecture - paper not submitted)
M. GOLA Y I Attempt to Apply the U B V Bl B2 VI G Photometry to the Deter-
mination of the Distance of the Hyades 27
R. E. SCHILD I A Far-Ultraviolet Flux Difference Between Hyades and Pleiades
Stars 31
D. H. P. JONES and D. W. CARRICK I Photo-Electric Measures of Hx and HP
in the Scorpio-Centaurus Association 36
A. MAEDER I Rotational Effects on the Photometric Determinations of Absolute
Magnitudes for A- and F-type Stars 41
PART III I CALIBRATION OF SPECTROSCOPIC
PARALLAXES
A. BLAAUW I The Calibration of Luminosity Criteria (Survey Lecture) 47
H. NECKEL and P. KLAWITTER I Absolute Magnitudes and Colours of Field
Giant Branch Stars 57
M. K. v. BAPPU I On the K-line Width-Absolute Magnitude Relation 64
VI TABLE OF CONTENTS
PH. C. KEENAN / Luminosity Calibration of Giants and Supergiants, GO--M5, 68
L. DIV AN / Calibration en magnitudes absolues de la classification BCD. Appli
a
cation la determination du module de distance du Grand Nuage de Magellan 78
E. B. NEWELL / The (log g, log Teff)-Diagram, a Fundamental HR-Diagram 86
PART IV / ABSOLUTE MAGNITUDE DETERMINATIONS
FROM HYDROGEN-LINE PHOTOMETRY
D. L. CRAWFORD / Absolute Magnitude Determinations from Hydrogen-Line
Photometry (Survey Lecture) 93
A. F. J. MOFFAT, TH. SCHMIDT-KALER, and N. VOGT / A Preliminary Test of
the Calibration of the HfJ System in Terms of Absolute Magnitudes and
Intrinsic Colours for Eady-Type Stars 114
B. HAUCK / Three-Dimensional Representation of AO-G5 Stars 117
D. CRAMPTON / The Hy-Absolute Magnitude Calibration 120
R. F. GARRISON / Calibration of MK Types by Fitting the HR Diagrams of
Three Moving Clusters 124
M. L. BURNICHON / Absolute Magnitudes of 0 Stars from a Study of Visual
Multiple Systems 126
PART V / GROUND BASED AND EXTRATERRESTRIAL
OBSERVATIONS OF STELLAR FLUX
A. D. CODE / Ground Based and Extraterrestrial Observations of Stellar Flux
(Survey Lecture) 131
P. L. BERNACCA / Line Blanketing in Real Stellar Atmospheres 146
H. NECKEL and D. LABS / Absolute Solar Intensities and the Solar Constant 149
H. KIENLE and D. LABS / Absolute Calibration of Stellar Temperatures 153
F. RUFENER and A. MAEDER / Comparison of Theoretical and Observed
Indices for Three Photoelectric Photometric Systems 156
S. TAPIA, H. L. JOHNSON, and D. L. CRAWFORD / First Results of the Absolute
Calibration of the u, v, b, y System of Filters 163
A. OPOLSKI / Radii and Fluxes of Long-Period Cepheids 165
PART VI/THE USE OF MODEL ATMOSPHERES
FOR TEMPERATURE
J. C. PECKER / The Use of Model Atmospheres for Temperature-Gravity Cali-
bration (Survey Lecture) 173
P. L. BERNACCA / Ultraviolet Energy Distribution of He-Weak Stars 222
R. D. MCCLURE / The Absolute Magnitude and Stellar Population of a Ba II
Star 225
TABLE OF CONTENTS vn
PART VII / STELLAR TEMPERATURE SCALE AND
BOLOMETRIC CORRECTIONS
J. R. w. HEINTZE / Stellar Temperature Scale and Bolometric Corrections
(Survey Lecture) 231
PART VIII/CHOICE OF STANDARD STARS
M. GOLAY / Remarks on the Photometric Criteria of Choice of the Standard
Stars (Survey Lecture) 275
F. RUFENER and A. MAEDER / Determination of the Apparent V Magnitudes 298
D. CHALONGE, L. DIVAN, and c. T. HUA / Distribution de l'energie dans Ie
spectre ultraviolet de quelques etoiles 302
PREFACE
In connection with arranging IAU Symposium No. 50 on 'Spectral Classification and
Multicolour Photometry', sponsored by Commissions 45 and 25, it was decided to
exclude all calibration problems. Instead it was agreed that we should attempt to
arrange a separate symposium, dealing with the fundamental problems of the cali
bration of absolute magnitudes and temperatures of stars.
The Executive Committee of the IAU accepted our proposal, and IAU Symposium
No. 54 was held in Geneva on September 12-15, 1972, sponsored by thefollowing IAU
Commissions: 24, 25, 29, 33, 35, 37,44 and 45. It was attended by about 90 scientists
representing 16 countries.
The Symposium was divided into eight sessions. Each session started with a review
paper by an invited speaker; this was followed by a general discussion including a few
contributed papers.
The contents of the present volume follow closely the programmes of the individual
sessions of the Symposium. Most of the recorded discussions have been kept, and only
in a few cases have the order of questions and comments been altered so as to obtain
more homogeneity in the presentation.
Financial assistance was provided by the Executive Committee of the International
Astronomical Union for travel grants to certain participants. Some travel grants were
also supplied by the 'Fonds national suisse de la recherche scientifique'. We are grate
ful to the Universities of Geneva and Lausanne for additional support such as
secretarial help and other facilities. Mrs M. Zuger and Miss B. Zwenzner are grate
fully acknowledged for their assistance at all stages of preparation of the present
volume.
SCIENTIFIC ORGANIZING COMMITTEE
C. Jaschek (Chairman), A. D. Code, D. L. Crawford, Y. Fujita, M. Golay,
W. J. Luyten, V. L. Straizys, H. C. Thomas, B. E. Westerlund
LOCAL ORGANIZING COMMITTEE
M. Golay (Chairman), B. Hauck, F. Rufener, U. Steinlin, R. West
PART I
ABSOLUTE MAGNITUDES
FROM TRIGONOMETRIC AND
STATISTICAL PARALLAXES
ABSOLUTE MAGNITUDES FROM TRIGONOMETRIC
AND STATISTICAL PARALLAXES
P. VAN DE KAMP
Sproul Observatory, Swarthmore College, Swarthmore, Pa., U.S.A.
Abstract. The attainable accuracy of photographic trigonometric parallaxes may be improved by the
use of modern measuring engines, larger number of exposures, facilitated by increased speed of
emulsions, more refined knowledge of reduction to absolute parallax. Systematic errors remain an
obstacle both in trigonometric and statistical parallaxes.
With an attainable goal of ± 0';002 for the probable error of a parallax it appears difficult to ob
tain absolute magnitudes with a probable error less than 0.2 mag. for stars beyond 20 pc.
I believe that the best contribution I can make to the subject of absolute magnitudes
is a presentation of the attainable accuracy in trigonometric parallaxes and a brief
reference to the same problem in statistical parallaxes.
The evaluation of the accuracy of determining trigonometric annual parallaxes has
been frequently studied and reported. Among the exhaustive studies, I mention those
by Land (1948), Strand (1963), and Lippincott (1970). It is not easy to improve on
these investigations but perhaps some general remarks may be in order today.
Greater accuracy may be reached in several ways. There is (1) the obvious choice of
observing times, (2) the potential increase in accuracy due to the vastly increased speed
of photographic emulsions, (3) the introduction of new measuring techniques,
(4) better knowledge of reduction from relative to absolute parallax, (5) elimination of
orbital motion in the case of series of observations covering a long time interval, both
for known visual binaries and perturbations, (6) recognition and possible elimination
of systematic errors, which vary with the interval of observation, (7) as far as absolute
magnitudes are concerned: recognition of duplicity in order to obtain proper absolute
magnitudes of the components.
1. Observing Times
Ideally, or rather traditionally, long focus photographic parallax observations are
made at dawn and at dusk, for the purpose of obtaining the largest possible range in
parallax factors in right ascension. The extreme range thus obtainable varies with the
position of the star in the sky, the observer's latitude, and the pattern of clear nights
as it varies with the time of the year. A large range in parallax factors, up to a maximum
of 2.0, may be obtained for stars in certain right ascensions, while in other parts of the
sky, at best, one has to be satisfied with smaller range, say only 1.5, and this may not even
be possible if weather conditions are unfavorable. As a rule a smaller range in right
ascension is accompanied by a larger range of parallax factors in declination. At the
Sproul Observatory, as a matter of policy, all stars are measured in declination also,
not primarily for parallax, but for the obvious purpose of observing orbital motion
B. Hauck and B. E. Westerlund (eds.), Problems of Calibration of Absolute Magnitudes and Temperature of Stars, 3-10.
All Rights Reserved. Copyright © 1973 by the [AU.