Subaru High-Resolution Spectroscopy of Star G in the Tycho Supernova Remnant

It is widely believed that Type Ia supernovae (SNe Ia) originate in binary systems where a white dwarf accretes material from a companion star until its mass approaches the Chandrasekhar mass and carbon is ignited in the white dwarf's core. This scenarioW.E.K., B.P.S., and M.A. are supported by the Australian Research Council (grant DP0559024, FF0561481). This paper was conceived as part of the Tokyo Think Tank collaboration, and was supported in part by the National Science Foundation under grant PHY05-51164. This work was supported in part by World Premier International Research Center Initiative (WPI Program), MEXT, Japan, and by the Grant-in-Aid for Scientific Research of the Japan Society for the Promotion of Science (18104003, 18540231, 20540226) and MEXT (19047004, 20040004)