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Paper: Measuring Evolutionary Rates
Volume: 334, 14th European Workshop on White Dwarfs
Page: 501
Authors: Kepler, S.O.; Costa, J.E.S.; Mukadam, A.; Mullally, F.; Winget, D.E.; Nather, R.E.; Sullivan, D.
Abstract: We have been using extensive data sets of time series photometry acquired over the last three decades to measure the rate of change of the pulsation periods of white dwarf stars, which in turn measure their evolutionary rates. The evolution of an isolated white dwarf is dominated by cooling. However, hot pre white dwarfs also show significant radius evolutionary rates. After 30 years of observations we finally measured the cooling rate of a DAV, G117−B15A, in good agreement with the theoretical predictions. But other periodicities for G117−B15A, and a similar DAV, R 548, show faster rates of period changes. We also observe faster evolutionary rates in other classes of white dwarf variables, e.g., the DOV PG1 159−035 and the DBV GD 358. These fast changes are not explained by the theoretical models to date.
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