The Stellar Population of h and chi Persei: Cluster Properties, Membership, and the Intrinsic Colors and Temperatures of Stars

Nov, 2009
88 pages
Published in:
  • Astrophys.J.Suppl. 186 (2010) 191-221
e-Print:

Citations per year

201020132016201920220123456
Abstract: (arXiv)
(Abridged) From photometric observations of \sim 47,000 stars and spectroscopy of \sim 11,000 stars, we describe the first extensive study of the stellar population of the famous Double Cluster, h and χ\chi Persei, down to subsolar masses. Both clusters have E(B-V) \sim 0.52--0.55 and dM = 11.8--11.85/ the halo population, while more poorly constrained, likely has identical properties. As determined from the main sequence turnoff, the luminosity of M supergiants, and pre-main sequence isochrones, ages for h Persei, χ\chi Persei and the halo population all converge on \approx 14 Myr. From these data, we establish the first spectroscopic and photometric membership lists of cluster stars down to early/mid M dwarfs. At minimum, there are \sim 5,000 members within 10' of the cluster centers, while the entire h and χ\chi Persei region has at least \sim 13,000 and as many as 20,000 members. The Double Cluster contains \approx 8,400 M_{\odot} of stars within 10' of the cluster centers. We estimate a total mass of at least 20,000 M_{\odot}. We conclude our study by outlining outstanding questions regarding the properties of h and χ\chi Persei. From comparing recent work, we compile a list of intrinsic colors and derive a new effective temperature scale for O--M dwarfs, giants, and supergiants.