Extensive observations from the Kepler spacecraft have recently revealed a new outburst phenomenon operating in cool pulsating DA (hydrogen atmosphere) white dwarfs (DAVs). With the introduction of two new outbursting DAVs from K2 Fields 7 (EPIC 229228364) and 8 (EPIC 220453225) in these proceedings, we presently know of six total members of this class of object. We present the observational commonalities of the outbursting DAVs: (1) outbursts that increase the mean stellar flux by up to 15%, last many hours, and recur irregularly on timescales of days; (2) effective temperatures that locate them near the cool edge of the DAV instability strip; and (3) rich pulsation spectra with modes that are observed to wander in amplitude/frequency.
@article{arxiv.1609.09097,
title = {The First Six Outbursting Cool DA White Dwarf Pulsators},
author = {Keaton J. Bell and J. J. Hermes and M. H. Montgomery and D. E. Winget and N. P. Gentile Fusillo and R. Raddi and B. T. Gänsicke},
journal= {arXiv preprint arXiv:1609.09097},
year = {2016}
}
Comments
6 pages, 2 figures, 1 table. To appear in the ASP Conference Series proceedings of "20th European Workshop on White Dwarfs," held at the University of Warwick, UK on July 25-29th, 2016