view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Effects of Stellar Rotation on the Colors and Magnitudes of Stars in Praesepe. Dickens, R. J. ; Krzeminski, W. ; Kraft, R. P. Abstract Rotational velocities have been determined by J. D. McGee, A. Khogali, W. A. Baum, and R. P. Kraft (Monthly Notices Roy. Astron. Soc., to be published) using an electronographic image tube, and also using conventional spectroscopy, for virtually all the stars in Praesepe brighter than V= 9.6 mag. New UB V photoelectric observations have been made for all the stars for which rotations are available. The photometry is combined with that obtained much earlier by H. L. Johnson (Astrophys. J. 116, 640, 1952). The brighter stars in Praesepe appear to rotate on the average about 15% faster than those in the Hyades at the same absolute magnitude. Theory indicates that stellar rotation should change the effective temperature, surface gravity, and absolute magnitude of a star. The effects on the temperature and surface gravity have been investigated in the U-B/B - V diagram. A weak correlation of ultraviolet excess with departure from mean rotation (at a given color) is obtained, although rather less pronounced than that found earlier in the Hyades (Kraft, R., and Wrubel, M., Astrophys. J. 142, 703,1965). The effect of rotation on absolute magnitude has been investigated in the color-magnitude diagram, in a manner similar to that followed by P. Strittmatter (Astrophys. J. 144, 430, 1966), who analyzed the same cluster but used less accurate rotations by Treanor and included fewer stars in the analysis. A much weaker correlation of magnitude excess with rotation excess (from the mean at a given color) is found using the new data. This result is more nearly in accord with the smaller effects predicted by models in uniform rotation than those in nonuniform rotation. Publication: The Astronomical Journal Pub Date: 1967 DOI: 10.1086/110432 Bibcode: 1967AJ.....72Q.793D full text sources ADS |