Discovery of a Cool, Massive, and Metal-rich DAZ White Dwarf

We report the discovery of a new metal-rich DAZ white dwarf, GD 362. High signal-to-noise ratio optical spectroscopy reveals the presence of spectral lines from hydrogen as well as Ca I, Ca II, Mg I, and Fe I. A detailed model atmosphere analysis of this star yields an effective temperature of T eff = 9740 ± 50 K, a surface gravity of log g = 9.12 ± 0.07, and photospheric abundances of log = -5.2 ± 0.1, log = -4.8 ± 0.1, and log = -4.5 ± 0.1. White dwarf cooling models are used to derive a mass of 1.24 M ☉ for GD 362, making it the most massive and metal-rich DAZ star uncovered to date. The problems related to the presence of such large metal abundances in a nearby ( d ~ 25 pc) white dwarf in terms of an accretion scenario are briefly discussed.