Axial Rotation in the Brighter Stars of Draper Types B2-B5.

Abstract

view Abstract Citations (114) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Axial Rotation in the Brighter Stars of Draper Types B2-B5. Slettebak, Arne ; Howard, Robert F. Abstract Rotational velocities (v sin i) of the stars of Draper types B2-B5, brighter than 5.51 mag. and north of declination - 20 , were determined by comparing observed profiles of the He 1 4471 line with sets of profiles computed by the graphical method of Shajn and Struve. Spectral types and luminosity classes on the MK system of classification were provided by Dr. W. W. Morgan. The mean true rotational velocity of the main-sequence stars of MK types B2-B5 was found to be 201 kin/sec, a value somewhat larger than the corresponding one for the stars. A subdivision of the main-sequence stars mto MK types and BSB7 shows that the BSB7 stars appear to have the greatest axial rotation, with decreasing rotational velocities for both earlier and later types. The stars of intermediate luminosity have smaller axial rotation than the main-sequence stars. This was also found to be the case for the stars, but the opposite situation was obtained for the stars. A number of spectroscopic binaries included in this study are discussed from the point of view of possible synchronism between axial rotation and orbital revolution. The luminosity effect of the forbidden line of He I at X 4470 is briefly discussed. It is suggested that the observed relation of axial rotation to position on the H-R diagram may be interpreted in terms of the evolutionary sequences recently computed by Sandage and Schwarzschild. Publication: The Astrophysical Journal Pub Date: January 1955 DOI: 10.1086/145968 Bibcode: 1955ApJ...121..102S full text sources ADS | data products SIMBAD (185)