Map-based trigonometric parallaxes of open clusters: Coma

Abstract

view Abstract Citations (13) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS MAP-based Trigonometric Parallaxes of Open Clusters: Coma Gatewood, George Abstract This is the fourth study in a series to determine the direct trigonometric parallaxes of four of the nearest open star clusters, the Hyades, the Pleiades, the Praesepe, and the nearby cluster in Coma (Gatewood et al. 1990; Gatewood et al. 1992); Gatewood & Kiewiet de Jonge 1994). The results for the open star cluster in Coma are compared with those of the other three clusters, and the members are found to be significantly subluminous. The trigonometric parallax of the cluster is estimated from that of three members studied with the Multichannel Astrometric Photometer (MAP) at the Thaw Refractor of the University of Pittsburgh's Allegheny Observatory. The weighted mean parallax of the cluster is +13.53 +/- 0.54 mass (0.00054 min), corresponding to a distance modulus of 4.34 +/- 0.09 mag. The U-B excess of the Coma cluster members may be used to adjust the observed absolute magnitudes and the B-V measurements as suggested by Sandage & Eggen (1959). The agreement obtained in this manner suggests that, like subdwarf stars, the stars of the Coma cluster appear subluminous because of line blanketing. One of the three members observed in this study was recognized as a member by its parallax and is the faintest known member of the cluster. Publication: The Astrophysical Journal Pub Date: June 1995 DOI: 10.1086/175733 Bibcode: 1995ApJ...445..712G Keywords: Astrography; Astrometry; Open Clusters; Stellar Parallax; Trigonometry; Data Reduction; Distance; Magnitude; Stellar Luminosity; Stellar Motions; Astrophysics full text sources ADS | data products SIMBAD (14) Related Materials (4) Part 1: 1990ApJ...364..114G Part 2: 1992ApJ...392..710G Part 3: 1994ApJ...428..166G Part 5: 2000ApJ...533..938G