A New Timescale for Period Change in the Pulsating DA White Dwarf WD 0111+0018

Abstract

We report the most rapid rate of period change measured to date for a pulsating DA (hydrogen atmosphere) white dwarf (WD), observed in the 292.9 s mode of WD 0111+0018. The observed period change, faster than 10^{-12} s/s, exceeds by more than two orders of magnitude the expected rate from cooling alone for this class of slow and simply evolving pulsating WDs. This result indicates the presence of an additional timescale for period evolution in these pulsating objects. We also measure the rates of period change of nonlinear combination frequencies and show that they share the evolutionary characteristics of their parent modes, confirming that these combination frequencies are not independent modes but rather artifacts of some nonlinear distortion in the outer layers of the star.

10 pages, 6 figures, accepted for publication in The Astrophysical Journal

References in corpus (6)

• Pulsating White Dwarf Stars and Precision Asteroseismology
• Toward ensemble asteroseismology of ZZ Ceti stars with fully evolutionary models
• The rate of cooling of the pulsating white dwarf star G117$-$B15A: a new asteroseismological inference of the axion mass
• Mapping the ZZ Ceti Instability Strip: Discovery of 6 New Pulsators
• Fine Grid Asteroseismology of R548 and G117-B15A
• Empirical Determination of Convection Parameters in White Dwarfs I : Whole Earth Telescope Observations of EC14012-1446

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