A Spectroscopic Survey & Analysis of Bright, Hydrogen-Rich White Dwarfs

TL;DR

This study presents a comprehensive spectroscopic survey of over 1100 bright hydrogen-rich white dwarfs, analyzing their atmospheric properties, classifications, and distributions, and comparing results with other surveys to refine understanding of white dwarf characteristics.

Contribution

The paper provides the largest homogeneous spectroscopic analysis of bright DA white dwarfs, incorporating updated models and techniques, and offers new insights into their properties and classifications.

Findings

Refined mass and temperature distributions of white dwarfs.

Identification of misclassified and peculiar white dwarfs.

Impact of new Stark broadening profiles on atmospheric parameter determination.

Abstract

We have conducted a spectroscopic survey of over 1300 bright (V < 17.5), hydrogen-rich white dwarfs based largely on the last published version of the McCook & Sion catalog. The complete results from our survey, including the spectroscopic analysis of over 1100 DA white dwarfs, are presented. High signal-to-noise ratio optical spectra were obtained for each star and were subsequently analyzed using our standard spectroscopic technique where the observed Balmer line profiles are compared to synthetic spectra computed from the latest generation of model atmospheres appropriate for these stars. First, we present the spectroscopic content of our sample, which includes many misclassifications as well as several DAB, DAZ, and magnetic white dwarfs. Next, we look at how the new Stark broadening profiles affect the determination of the atmospheric parameters. When necessary, specific models and analysis techniques are used to derive the most accurate atmospheric parameters possible. In particular, we employ M dwarf templates to obtain better estimates of the atmospheric parameters for those white dwarfs that are in DA+dM binary systems. Certain unique white dwarfs and double-degenerate binary systems are also analyzed in greater detail. We then examine the global properties of our sample including the mass distribution and their distribution as a function of temperature. We then proceed to test the accuracy and robustness of our method by comparing our results to those of other surveys such as SPY and SDSS. Finally, we revisit the ZZ Ceti instability strip and examine how the determination of its empirical boundaries are affected by the latest line profile calculations.