Searching for Boyajian’s Star Analogs with the Zwicky Transient Facility

The Zwicky Transient Facility (ZTF) survey is a treasure trove for time domain science, and members of DiRAC’s Time Domain & Inference group are collaborating to comb through some 200 million light curves to search for candidate Boyajian’s Star analogs.

Boyajian’s Star is a unique F star observed by the Kepler Space Telescope to have repeated, infrequent short-term variability (“dips”) and a long-term gradual decrease in brightness. The physical cause of the variability is not understood. One of the big questions is still there, is it unique or are there a whole families that have a similar patterns of variability.

We have developed a tool to find similar light curve dips and applied it to stars observed by ZTF in a 2000-square-degree region of sky that has been observed in a high-cadence mode. Of about 180 million total objects with high-cadence light curves, we found 40,000 potential dippers.

The bulk of the work on this project has been accomplished during weekly group meetings, where one person shares their screen and we all collaboratively write code and make plots. This innovative group project was proposed by James Davenport, and Kyle Boone has taken the lead on much of the computational work. Other contributors include Meredith Rawls, Colin Slater, Keaton Bell, Eric Bellm, Brigitta Sipocz, Bryce Kalmbach, and Daniela Huppenkothen.

We are now working to cross-match these sources with Gaia, WISE, and other survey catalogs to eliminate known variables such as young stellar objects and eclipsing systems. We will present the results of the project at a poster at the 235th AAS meeting in January 2020.