Four new deeply eclipsing white dwarfs in Zwicky Transient Facility

A Kosakowski, M Kilic, WR Brown… - Monthly Notices of …, 2022 - academic.oup.com
A Kosakowski, M Kilic, WR Brown, P Bergeron, T Kupfer
Monthly Notices of the Royal Astronomical Society, 2022academic.oup.com
We present the results of a search for deeply eclipsing white dwarfs in the Zwicky Transient
Facility (ZTF) Data Release 4 (DR4). We identify nine deeply eclipsing white dwarf
candidates, four of which we followed up with high-cadence photometry and spectroscopy.
Three of these systems show total eclipses in the ZTF data and our follow-up Apache Point
Observatory 3.5 m telescope observations. Even though the eclipse duration is consistent
with sub-stellar companions, our analysis shows that all four systems contain a white dwarf …
Abstract
We present the results of a search for deeply eclipsing white dwarfs in the Zwicky Transient Facility (ZTF) Data Release 4 (DR4). We identify nine deeply eclipsing white dwarf candidates, four of which we followed up with high-cadence photometry and spectroscopy. Three of these systems show total eclipses in the ZTF data and our follow-up Apache Point Observatory 3.5 m telescope observations. Even though the eclipse duration is consistent with sub-stellar companions, our analysis shows that all four systems contain a white dwarf with low-mass stellar companions of ∼0.1 M. We provide mass and radius constraints for both stars in each system based on our photometric and spectroscopic fitting. Finally, we present a list of 41 additional eclipsing WD+M candidates identified in a preliminary search of ZTF DR7, including 12 previously studied systems. We identify two new candidate short-period, eclipsing, white dwarf–brown dwarf binaries within our sample of 41 WD+M candidates based on Pan-STARRS colours.
Oxford University Press