SDSS White Dwarfs with Spectra Showing Atomic Oxygen and/or Carbon Lines

Citation:

Liebert J, Harris HC, Dahn CC, Schmidt GD, Kleinman SJ, Nitta A, Krzesiński J, Eisenstein D, Smith AJ, Szkody P, et al. SDSS White Dwarfs with Spectra Showing Atomic Oxygen and/or Carbon Lines. The Astronomical Journal. 2003;126 :2521-2528.

Date Published:

November 1, 2003

Abstract:

We discuss 18 white dwarfs, one of which (G227-5) was previously known,whose SDSS spectra show lines of neutral and/or singly ionized carbon.At least two and perhaps four show lines of neutral or singly ionizedoxygen. Apart from the extremely hot ``PG 1159'' stars, these are thefirst white dwarfs with photospheric oxygen detected in their opticalspectra. The photometry strongly suggests that these stars lie in the11,000-30,000 K temperature range of the helium-atmosphere DB whitedwarfs, though only one of them shows weak neutral helium lines in thespectrum. Trigonometric parallaxes are known for G227-5 and another,previously known white dwarf (G35-26) showing atomic carbon lines, andthey indicate that both are massive stars. Theoretical arguments suggestthat all members of this class of rare white dwarfs are massive (~1Msolar), and this finding could explain the paucity ofmassive DB white dwarfs.

Notes:

n/a

Website