Re-defining the Empirical ZZ Ceti Instability Strip
Abstract
We use the new ZZ Ceti stars (hydrogen atmosphere white dwarf variables; DAVs) discovered within the Sloan Digital Sky Survey (Mukadam et al. 2004) to re-define the empirical ZZ Ceti instability strip. This is the first time since the discovery of white dwarf variables in 1968 that we have a homogeneous set of spectra acquired using the same instrument on the same telescope, and with consistent data reductions, for a statistically significant sample of ZZ Ceti stars. The homogeneity of the spectra reduces the scatter in the spectroscopic temperatures and we find a narrow instability strip of width ~950K, from 10850--11800K. We question the purity of the DAV instability strip as we find several non-variables within. We present our best fit for the red edge and our constraint for the blue edge of the instability strip, determined using a statistical approach.
Cite
@article{arxiv.astro-ph/0405591,
title = {Re-defining the Empirical ZZ Ceti Instability Strip},
author = {Anjum S. Mukadam and D. E. Winget and Ted von Hippel and M. H. Montgomery and S. O. Kepler and A. F. M. Costa},
journal= {arXiv preprint arXiv:astro-ph/0405591},
year = {2009}
}
Comments
14 pages, 5 pages, ApJ paper, accepted