Sirius B: A New, More Accurate View

Abstract

Long-standing questions regarding the temperature, gravity, mass, and radius of the well-known white dwarf Sirius B are considered in light of new data. Recently obtained Extreme Ultraviolet Explorer (EUV E) observations and reprocessed IUE NEWSIPS data have produced a new, well-dened e ective temperature of 24,790 ^100 K and a surface gravity of log g \ 8.57 ^0.06 for Sirius B. A new Hipparcos parallax for the Sirius system of is used in conjunction with the above n \ 0A .37921 ^0A .00158 spectroscopic results and the previously published gravitational redshift to yield a mass of 0.984 ^0.074 and a radius of for the white dwarf. Combining these results with M _ R \ 0.0084 ^0.00025R _ the existing astrometric mass for Sirius B gives a rened mass estimate of M \ 1.034 ^0.026