High-probability and confirmed white dwarfs observed by Kepler and K2

Interest in remnant exoplantery systems around white dwarfs has grown considerably after the discovery of the first transiting debris around a white dwarf in K2 Campaign 1, announced by Vanderburg et al. (2015). Since the beginning of K2, well more than 1700 candidate white dwarfs have been proposed by several groups to monitor for transits or variability: the approved targets and programs (detailed at the K2 Guest Observer website) have been mostly led by PIs Redfield, Kilic, Burleigh, Kawaler, and Hermes.

However, these candidate lists include dozens of duplications, and dozens more that are spectroscopically known not to be white dwarfs -- there is at least a 10% contamination fraction of candidate white dwarf lists. Moreover, another 135+ through K2 Campaign 15 are composite WD+dM binaries, with the dM contributing most of the flux in the Kepler bandpass. Any occurrence rate study based simply on white dwarf candidate lists suffers from nearly 20% contamination from non-WDs, duplications, and WD+dM systems.

To mitigate non-WD and duplicate contamination in white dwarf exoplanet studies, we have compiled a list of high-confidence white dwarfs observed by Kepler from the original mission through K2 Campaign 15.

The catalog is a comma-separated variable file with fields corresponding to: K2 Campaign (Field), Shortest Cadence Available (ShortestCadence), KIC/EPIC ID (ID), RA (J2000), Declination (J2000), Source Classification (Classification), Probability of Being WD (PWD), K2 GO Proposal (Investigation ID), Kepler Module (Module), Kepler Output (Output), and Kepler Channel (Channel).

When available, PWD is computed from SDSS or VST ATLAS photometry by Gentile Fusillo et al. 2015 and Gentile Fusillo et al. 2017, respectively.

The classification can be broken down by a number of sources. Most confident are targets that have been spectroscopically classified in the literature (Spectroscopic). We have included all composite WD+dM systems in this list (see sdss-wdms.org), some of which are post-common-envelope binaries, but most of which are wide binaries (Spectroscopic_WDMSComposite). We list all objects with PWD > 0.1 in this catalog (PWD), but only have high confidence in targets with PWD > 0.7. Finally, a handful of systems are candidate white dwarfs from the McCook & Sion catalog (CandMcCook&Sion).

Feel free to utilize this catalog for any purpose, but please contact JJ Hermes (jjhermes@unc.edu) if you plan to use this catalog in a publication. Old versions of this list exist through Campaign 10, Campaign 13, and Campaign 14. The current list of the more than 1610 high-probability white dwarfs as of 1 February 2018, through Campaign 15, is available below: