The open cluster NGC 6791 is now considered both the oldest and the most metal-rich known. Its age is 8 -10 Gyrs, twice as old as the canonical solar-metallicity cluster M67 (Garnavich et al. 1994; Demarque, Green, & Guenther 1992; Tripicco et al. 1995). That its metallicity is significantly above solar is suggested from moderate-resolution spectroscopy and from a mismatch of its color-magnitude diagram (CMD) with solar-metallicity isochrones. Tripicco et al. (1995) find [Fe/H] = +0.27 to +0.44. The cluster population is rich. In addition to about a dozen red giants and two dozen red horizontal-branch stars, the cluster has several very hot HB stars (Kaluzny & Udalski 1992). Liebert et al. (1994) have shown that the extremely blue stars are mostly sdB/sdO stars and at least 3 or 4 are likely cluster members, the first ever discovered in an open cluster. These may provide the key to the puzzling upturn in ultraviolet flux below 1500A seen in many high-metallicity systems (Burstein et al. 1988; Ferguson et al. & Liebert 1993).
Conference papers in order of presentation: Big Bang nucleosynthesis, D.N. Schramm; light elements abundances - new insights on stellar mixing and galactic production, F. Primas; the first stars, D. Arnett; Type 1A supernovae and chemical evolution of galaxies, K. Nomoto, et al; the chemical evolution of light elements in our galaxy, N. Prantzos; nucleosynthesis in red giant stars, N. Mowlavi; fluorine production from AGB and WR stars, N. Mowlavi, G. Meynet; deuterium abundance in the local ISM, J.L. Linsky, B.E. Wood; abundances in halo population stars, C. Sneden; abundances in the galactic disk, B. Edvardsson; abundances in a hot horizontal-branch star in the old open cluster NGC/6791, R.C. Peterson, E.M. Green; on the progenitors of type Ia supernovae, X.-D. Li, E.P.J. van den Heuvel; abundances from z = 0 to z = 5, D.G. York; enrichment of heavy elements in clusters of galaxies, Y. Ishimaru; on the origin of metallicity in Lyman-Alpha forest systems, M. Chiba, B.B. Nath; a metal enriched dark cluster of galaxies at Z = 1; M. Hattori; are elliptical galaxies really metal-rich? M. Loewenstein, R.F. Mushotzky; chemical evolution of spiral galaxies from redshift 4 to the present, U. Fritze-v. Alvensleben, et al; age problem based on the abundance ratio from a high-redshift QSO, T. Tsujimoto, et al; stellar yields and chemical evolution, B.K. Gibson; the formation of first generation stars and globular clusters in protogalactic clouds, D.N.C. Lin, S.D. Murray. (Part contents).
Series: International Astronomical Union Symposia
Number Of Pages: 242
Published: 31st March 2002
Publisher: Springer-Verlag New York Inc.
Country of Publication: US
Dimensions (cm): 24.0 x 16.0
Weight (kg): 0.41