Year: 1967
Type: article
Abstract: The four-color data of Stromgren and Perry (Astrophys. J., to be published) and the H~ photometry of Crawford et al. (Astron. J. 71, 1966) have been used to calibrate the intrinsic color (by)0 of the uvby system in terms of p, Ac1, and Am1. The parameter Ac1 is the difference between the measured c1 and a zero-age line in a c1 vs p relation. For A and F stars, it is a measure of relative luminosity for stars of the same temperature. The parameter Am1 is the difference between the measured m1 and the average relation for the Hyades (Crawford and Perry, Astron. J. 71, 206, 1966). It is a measure of the relative line blanketing near 4100 A. of the 1217 stars in the Stromgren- Perry catalogue, 379 were omitted as being outside the range of A2 to GO main sequence stars, and 13 as obviously reddened. The 825 remaining stars were divided into seven p groups, and a solution of the form (b -y)o = A +Bp+CAc1+DAm1 was obtained for each group. For the five groups of earliest spectral type, a mean deviation of + 0W01 1 (for one star) was found. For the two latest spectral groups it was +0rn.014. The coefficients of Ac1 and Am are small in all cases, and hence p is a very good predictor of intrinsic color. One can also state that very few of the A and F type main sequence stars brighter than V= 6'~5 are reddened by interstellar absorption.
Source: The Astronomical Journal
DOI: 10.1086/110570
Authors: D. L. Crawford, Bengt Stromgren
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2060717521