A detailed spectroscopic analysis of the open cluster NGC 5460

L. Fossati, C.P. Folsom, S. Bagnulo, J.H. Grunhut, O. Kochukhov, J.D. Landstreet, C. Paladini, G.A. Wade

Figure 1. Comparison between the observed Hβ line profile (thick lines) and synthetic line profile (thin lines) for seven stars observed with FLAMES/GIRAFFE. From top to bottom the stars here displayed are: UCAC 11104969 (T_eff = 7050 K), UCAC 11105106 (T_eff = 7500 K), UCAC 11105176 (T_eff = 8100 K), CPD-47 6385 (T_eff = 9350 K), CD-47 8868 (T_eff = 10400 K), HD 123202 (T_eff = 11400 K) and HD 123226 (T_eff = 12400 K). Profiles are vertically offset for display purpose.

ABSTRACT
Within the context of a large project aimed at studying early F-, A- and late B-type stars we present the abundance analysis of the photospheres of 21 members of the open cluster NGC 5460, an intermediate age cluster (log tòÈ® 8.2) previously unstudied with spectroscopy. Our study is based on medium and high resolution spectra obtained with the FLAMES instrument of the ESO/VLT. We show that cluster members have a nearly solar metallicity, and that there is evidence that the abundances of magnesium and iron are correlated with the effective temperature, exhibiting a maximum around T_eff = 10500 K. No correlations are found between abundances and projected equatorial velocity, except for marginal evidence of barium being more abundant in slower than in faster rotating stars. We discovered two He-weak stars, and a binary system where the hotter component is a HgMn star. We provide new estimates for the cluster distance (720 ± 50 pc), age (log t = 8.2 ± 0.1), and mean radial velocity (òÈÒ17.9 ± 5.2 km s^òÈÒ1).

Full paper in PDF format

Last Revised: 2011 January 4th