NGC 2516 and the Pleiades Group

Abstract

view Abstract Citations (80) References (52) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS NGC 2516 and the Pleiades Group Eggen, O. J. Abstract UBV observations to visual magnitude 16 are given for stars in NGC 2316 together with new UBV observations of members of IC 2602 and 2391 and intermediate-band results for the members of the Sculp toris cluster. The clusters of the Pleiades group are found to represent a considerable age spread (1-8 x 10 years), and this is confirmed by both the luminous blue and red group members unattached to clusters. The B-type stars in the younger (a Persei) and older (Pleiades and NGC 2516) group clusters closely define the same relation between the H intensities and the luminosities, but the young group cluster IC 2602 and the similar, non-group cluster IC 2391 give anomalous results both in the ( Iv, P) -relation of the hot stars and in the luminosities derived from the A-type and F- and G-type main-sequence stars from the intermediate-band indices. The early-type group members in the general field, including several of the brightest members of the Scorpius-Centaurus stream, appear to represent the same age spread as the clusters in the group and also define the same (3fv, P) -relation as the B-type stars in the a Persei and Pleiades clusters. The clusters in the group contain several late-type high-luminosity stars, and the group members in the general field include such bright stars as a Car, a Sco, and several F- and G-type objects of luminosity class IL The distribution of group members in the ( Ibo1, log T -plane is understandable in terms of evolutionary tracks for stellar models of masses 3-13 . The lower limit of the temperature of the luminous group stars is some 600 hotter than for the members of the older Hyades group, and this probably explains the apparent absence of "normal" red variables in the Pleiades group. However, the group probably contains the hotter, erratic N-type variables at near -5 mag. Publication: The Astrophysical Journal Pub Date: April 1972 DOI: 10.1086/151401 Bibcode: 1972ApJ...173...63E full text sources ADS | data products SIMBAD (294) NED (1) GCPD (1)