Temperatures and surface gravities of DB white dwarfs

Abstract

view Abstract Citations (74) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Temperatures and surface gravities of DB white dwarfs. Oke, J. B. ; Weidemann, V. ; Koester, D. Abstract Multichannel observations or reobservations of all DB white dwarfs accessible from Palomar Observatory, reduced and calibrated with the AB79 program of Oke and Gunn (1983), have been compared by least squares fitting procedures with energy distributions calculated from new model atmospheres with He:H = 100,000 and reduced metal content He:C = 1,000,000. The surface gravities and temperatures derived reveal for the first time a definitive cooling sequence for the DB stars, with a narrow mass distribution comparable to that of the DA white dwarfs. The mass range, 0.55 + or - 0.10 solar mass, almost coincides with the range derived for DA, DC, and C2 stars and therefore suggests that the progenitors for all these stars are the same. Spectroscopic distance determinations and comparison with cooling ages demonstrate that DB stars account for about one-tenth of the total white dwarf birthrate. Publication: The Astrophysical Journal Pub Date: June 1984 DOI: 10.1086/162097 Bibcode: 1984ApJ...281..276O Keywords: Stellar Atmospheres; Stellar Evolution; Stellar Mass; Stellar Spectrophotometry; Stellar Temperature; White Dwarf Stars; Abundance; Least Squares Method; Spectral Energy Distribution; Stellar Gravitation; Astrophysics full text sources ADS | data products SIMBAD (35) MAST (1)