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A new calibration of the extragalactic distance scale using Cepheids and RR Lyrae starsVisual absolute magnitudes of classical Cepheids, metal-poor RR Lyrae stars and short-period type II Cepheids have been determined with very high precision by combining a large number of old and new astrophysical data. Five independent methods (four observational and one theoretical) have been successfully used: (1) secular and statistical parallaxes; (2) moving-group parallaxes; (3) cluster main-sequence fitting; (4) the Baade-Wesselink method and its modifications; and (5) light-curve and velocity-curve fitting (the theoretical method). With these five adopted methods, the zero point of the galactic and extragalactic distance scale can be set on a relatively firm and self-consistent basis. Classical Cepheids and RR Lyrae stars now provide essentially identical distances to nearby galaxies: the distance modulus to the Large Magellanic Cloud is 18.5 and to the Small Magellanic Cloud is 18.8, both with an uncertainty of 0.1. The distance to the center of our Galaxy is 8.6 plus or minus 0.5 kiloparsecs. The major uncertainty in these values lies in the correction for interstellar extinction.
Document ID
19840031844
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Stothers, R. B.
(NASA Goddard Institute for Space Studies New York, NY, United States)
Date Acquired
August 12, 2013
Publication Date
November 1, 1983
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 274
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
84A14631
Distribution Limits
Public
Copyright
Other

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