Binary Frequency as a Probable Index of Secular Changes in the Main Sequence.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Binary Frequency as a Probable Index of Secular Changes in the Main Sequence. Hynek, J. Allen Abstract As Aitken pointed out long ago, stars of late spectral type have a lower proportion of visual companions than do stars of early spectral type. This appears to apply to spectroscopic binaries as well. According to present theories of stellar evolution, this implies a secular change in the frequency of binaries along the main sequence. The reality of the binary frequency imbalance between giant and main sequence stars has been re-examined with emphasis on possible selection factors and on its relation to space motions of the stars concerned. The discussion is limited to the Yale Bright Stars, for which stars there exists maximum homogeneity of observations of multiplicity, radial velocity, and spectra. It is concluded that observational selection, difference in Population, and space motions are not sufficient to explain the deviation from a "steady-state" main sequence implied by the binary-poor nature of the present giant population. The more recently formed stars appear to have a marked increase in the number of binary stars. Publication: The Astronomical Journal Pub Date: 1965 DOI: 10.1086/109640 Bibcode: 1965AJ.....70S.140H full text sources ADS |