Astronomy & Astrophysics

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Issue		A&A Volume 419, Number 2, May IV 2004
Page(s)		L5 - L8
Section		Letters
DOI		10.1051/0004-6361:20040120

A&A 419, L5-L8 (2004)
DOI: 10.1051/0004-6361:20040120

Letter

Mass distribution of DA white dwarfs in the First Data Release of the Sloan Digital Sky Survey

J. Madej¹, M. Nalezyty¹ and L. G. Althaus²

¹ Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw, Poland
² Departament de Fisica Aplicada, Universitat Politecnica de Catalunya, Av. del Canal Olimpic s/n, 08860, Castelldefels, Spain

(Received 4 March 2004 / Accepted 23 March 2004)

Abstract
We investigate the sample of 1175 new nonmagnetic DA white dwarfs with the effective temperatures $T_{\rm eff} \ge 12\,000$ K, which were extracted from the Data Release 1 of the Sloan Digital Sky Survey. We determined masses, radii, and bolometric luminosities of stars in the sample. The above parameters were derived from the effective temperatures $T_{\rm eff}$ and surface gravities $\log g$ published in the DR1, and the new theoretical M-R relations for carbon-core and oxygen-core white dwarfs. Mass distribution of white dwarfs in this sample exhibits the peak at $M=0.562~ M_\odot$ (carbon-core stars), and the tail towards higher masses. Both the shape of the mass distribution function and the empirical mass-radius relation are practically identical for white dwarfs with either pure carbon or pure oxygen cores.

Key words: catalogs -- stars: fundamental parameters -- stars: white dwarfs

Offprint request: M. Nalezyty, nalezyty@astrouw.edu.pl

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