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Distance and absolute magnitudes of the brightest stars in the dwarf galaxy Sextans AIn an attempt to improve present bright star calibration, data were gathered for the brightest red and blue stars and the Cepheids in the Im V dwarf galaxy, Sextans A. On the basis of a magnitude sequence measured to V and B values of about 22 and 23, respectively, the mean magnitudes of the three brightest blue stars are V=17.98 and B=17.88. The three brightest red supergiants have V=18.09 and B=20.14. The periods and magnitudes measured for five Cepheids yield an apparent blue distance modulus of 25.67 + or - 0.2, via the P-L relation, and the mean absolute magnitudes of V=-7.56 and B=-5.53 for the red supergiants provide additional calibration of the brightest red stars as distance indicators. If Sextans A were placed at the distance of the Virgo cluster, it would appear to have a surface brightness of 23.5 mag/sq arcec. This, together with the large angular diameter, would make such a galaxy easily discoverable in the Virgo cluster by means of ground-based surveys.
Document ID
19820054494
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Sandage, A.
(Mount Wilson and Las Campanas Observatories Pasadena, CA, United States)
Carlson, G.
(Mount Wilson and Las Campanas Observatories, Pasadena; Citrus College, Azusa CA, United States)
Date Acquired
August 10, 2013
Publication Date
July 15, 1982
Publication Information
Publication: Astrophysical Journal
Subject Category
Astronomy
Accession Number
82A38029
Funding Number(s)
CONTRACT_GRANT: NAGW-118
Distribution Limits
Public
Copyright
Other

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