The DECam Minute Cadence Survey I

TL;DR

This study demonstrates the use of high-cadence DECam observations to identify white dwarf candidates and pulsators, setting the stage for future surveys to constrain the frequency of planets around white dwarfs.

Contribution

First minute-cadence survey using DECam to identify white dwarf candidates and pulsators, with initial results and non-detection of transiting planets.

Findings

Identified 111 high proper motion white dwarf candidates.

Discovered a new pulsating ZZ Ceti star.

No transiting planets found in the habitable zone.

Abstract

We present the first results from a minute cadence survey of a three square degree field obtained with the Dark Energy Camera. We imaged part of the Canada-France-Hawaii Telescope Legacy Survey area over eight half-nights. We use the stacked images to identify 111 high proper motion white dwarf candidates with g $\leq24.5$ mag and search for eclipse-like events and other sources of variability. We find a new g = 20.64 mag pulsating ZZ Ceti star with pulsation periods of 11-13 min. However, we do not find any transiting planetary companions in the habitable zone of our target white dwarfs. Given the probability of eclipses of 1% and our observing window from the ground, the non-detection of such companions in this first field is not surprising. Minute cadence DECam observations of additional fields will provide stringent constraints on the frequency of planets in the white dwarf habitable zone.