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arXiv · 1607.01392

Outbursts in two new cool pulsating DA white dwarfs

Keaton J. Bell·J. J. Hermes·M. H. Montgomery·N. P. Gentile Fusillo·R. Raddi·B. T. Gaensicke·D. E. Winget·E. Dennihy·A. Gianninas·P. -E. Tremblay·P. Chote·K. I. Winget
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Abstract

The unprecedented extent of coverage provided by Kepler observations recently revealed outbursts in two hydrogen-atmosphere pulsating white dwarfs (DAVs) that cause hours-long increases in the overall mean flux of up to 14%. We have identified two new outbursting pulsating white dwarfs in K2, bringing the total number of known outbursting white dwarfs to four. EPIC 211629697, with T_eff = 10,780 +/- 140 K and log(g) = 7.94 +/- 0.08, shows outbursts recurring on average every 5.0 d, increasing the overall flux by up to 15%. EPIC 229227292, with T_eff = 11,190 +/- 170 K and log(g) = 8.02 +/- 0.05, has outbursts that recur roughly every 2.4 d with amplitudes up to 9%. We establish that only the coolest pulsating white dwarfs within a small temperature range near the cool, red edge of the DAV instability strip exhibit these outbursts.

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Keaton J. Bell, J. J. Hermes, M. H. Montgomery, N. P. Gentile Fusillo, R. Raddi, B. T. Gaensicke, D. E. Winget, E. Dennihy, A. Gianninas, P. -E. Tremblay, P. Chote, K. I. Winget. 2016-07-05. Outbursts in two new cool pulsating DA white dwarfs. https://doi.org/10.3847/0004-637x%2F829%2F2%2F82

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