Spectral Investigation of Selected Bright Eclipsing Binary Systems.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectral Investigation of Selected Bright Eclipsing Binary Systems. Koch, Robert H. ; Olson, Edward C. ; Yoss, Kenneth M. Abstract Spectral classifications, hydrogen absolute magnitudes, and equatorial rotational velocities have been determined for component stars in 19 bright eclipsing binary systems, using calibrated 20 A/mm spectra obtained at the Mt. Wilson Observatory. Equivalent widths determined from M K standards form the basis of the classification. Widths measured in single- and double-line systems were corected for the influence of the second star. A scarcity of class III standards precluded the development of luminosity criteria, but the Petrie H~ method was applied to determine the absolute visual magnitudes. Resulting spectral classes and absolute magnitudes are internally consistent to ~0.1 and +0.2, respectively. Few of the stars (apart from subgiant components) fall far from the class V sequence given by Keenan [Vol. III ~f Stars and Stellar Systems, edited by K. Aa. Strand (University of Chicago Press, Chicago, 1963)J. Equatorial rotational velocities were determined by comparing the observed half-widths with those derived from rotational-broadening calculations based on profiles in sharp-line stars of similar spectral type. Axial-orbital synchronism was investigated, adopting radii (1) from available photometric and radial velocity solutions and (2) from the radiation law. Synchronism appears to be approximated but often not reached, departures occurring in the sense of a too rapid axial rotation. Comparison of the rotational velocities of eclipsing components and mean rotations of class V field stars and visual binaries (Slettebak, A., A strophys. J. 138, 118, 1963) shows the former to rotate considerably more slowly than the latter. This work was supported by the National Science Foundation. Publication: The Astronomical Journal Pub Date: 1964 DOI: 10.1086/109506 Bibcode: 1964AJ.....69T.547K full text sources ADS |