Four new deeply-eclipsing white dwarfs in ZTF

TL;DR

This paper reports the discovery of four new deeply-eclipsing white dwarf systems with low-mass stellar companions, along with a catalog of additional WD+M candidates, enhancing understanding of white dwarf binary populations.

Contribution

The study identifies four new deeply-eclipsing white dwarf binaries and provides detailed mass and radius measurements, along with a catalog of 41 additional WD+M candidates from ZTF data.

Findings

Four new deeply-eclipsing white dwarf systems discovered.

All systems contain low-mass stellar companions (~0.1 Msol).

A catalog of 41 additional WD+M candidates is presented.

Abstract

We present the results of a search for deeply-eclipsing white dwarfs in the ZTF Data Release 4. 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 APO 3.5-meter 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 Msol. 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 PanSTARRS colors.