Photospheric Silicon in the DA White Dwarf Wolf 1346

Abstract

We present a new coadded lUE echelle spectrum of the moderate temperature (T_eff ∼20,000 K) DA white dwarf Wolf 1346. In addition to previously reported stellar and interstellar features, we find a number of new stellar lines due to Si II and Si III. These silicon features have observed Doppler velocities near the +23 km s^-1 stellar photospheric velocity determined from the non-LTE core of the stellar Hα profile. The velocities and observed strengths of these lines are consistent with a photosperic origin. We derive a Si abundance of log(Si/H)=-7.5±0.2 which is comparable to the Si abundance expected from radiative levitation.