White Dwarfs: Search, Survey, Study, and Understand?

103.03

Improved Photometric Distances for White Dwarfs

1/8/2007 9:20:00 AM

1/8/2007 6:30:00 PM

08. White Dwarfs, Neutron Stars, & Pulsars

Jay B. Holberg¹, E. M. Sion², T. D. Oswalt^3
1Univ. of Arizona, ²Villanova University, ³Florida Institute of Technology.

Accurate distances and luminosities for white dwarfs help establish a number of basic observational properties for degenerate stars. Such collective properties as luminosity functions, space densities, and space motions are all tied directly to reliable distance estimates for large numbers of stars. As the number of direct trigonometric parallaxes will remain limited for the near future, we apply the recent results of improved photometric calibrations to large samples of white dwarfs having high quality optical and near IR photometry, as well as spectroscopic temperatures and gravities. Improved photometric distances (and luminosities) are estimated. Comparisons with trigonometric parallaxes and the determination of residual reddening will be discussed, as well as estimates of distance uncertainty.
This work is supported by NSF Grants AST 0507797 (JH) and AST 0206115 (TO).