Figure 1. Color-color diagrams showing the 49 variable objects as well as the non-variable objects. Credit: Dame et al. 2019
Astronomers recently submitted their findings identifying 49 new variable objects of which 40 are new systems to the Monthly Notices of the Royal Astronomical Society Journal (see Figure 1). Searching for variability over short time frames is a relatively new area of exploration that is enabled by large surveys searching for specific things like the optical counterparts to gravitational wave events, planetary transits, or supernovae. This study made use of the Dark Energy Camera (DECam), a 520 megapixel CCD camera on a 4 meter telescope in northern Chile. The study targeted 31,732 point sources in a 3 square degrees area over 8 consecutive nights. Specifically, the survey was looking for planetary transits around white dwarfs by taking images about every 90 seconds. Although no planets were found transiting white dwarfs, all the photometry was further analyzed to figure out which type variables they were. The variables discovered included twenty-three detached or contact binaries (see Figure 2), one eclipsing white dwarf, sixteen delta Scuti (see Figure 3), three RR Lyrae (see Figure 4), and two ZZ Ceti. These results highlight the ability of large, short time frame surveys to uncover interesting results, regardless of the intended target.
Figure 2. Light curves in the top two panels are contact binaries while the bottom panel is a detached binary. Credit: Dame et al. 2019
Figure 3. Phase folded light curves for delta Scuti variables. Credit: Dame et al. 2019
Figure 4. Phase folded light curves for RR Lyrae variables. Credit: Dame et al. 2019
