On the metallicity and the turnoff temperature of M67

Abstract

view Abstract Citations (63) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the Metallicity and the Turnoff Temperature of M67 Hobbs, L. M. ; Thorburn, J. A. Abstract The present study analyzes high-dispersion echelle spectra of five stars located along the main sequence of M67 using the model atmospheres of Kurucz (1979). An average iron abundance of the cluster, relative to the sun, of -0.04 or - 0.12 is derived from the observed equivalent widths of up to four weak Fe II lines in each of the five spectra and in the solar spectrum. The average temperatures of the two brightest hottest program stars approximate satisfactorily the upper limit on the temperatures actually reached in the turnoff region. A turnoff age of 5.2 + or - 1.0 Gyr is derived by comparing the limiting turnoff temperature to appropriate isochrones in the theoretical H - R diagram, as calculated by VandenBerg (1990). The primary advantage of the present method is that it effectively requires no estimates of the reddening or the intrinsic colors of the cluster stars or of the distance to the cluster; the attendant uncertainties in these cluster parameters are thereby circumvented entirely. Publication: The Astronomical Journal Pub Date: September 1991 DOI: 10.1086/115933 Bibcode: 1991AJ....102.1070H Keywords: Main Sequence Stars; Metallic Stars; Stellar Spectra; Stellar Temperature; Echelette Gratings; Open Clusters; Stellar Atmospheres; Astrophysics; CLUSTERS: OPEN; STARS: ATMOSPHERES full text sources ADS | data products SIMBAD (8)