The ASAS-SN catalogue of variable stars I: The Serendipitous Survey

TLDR

The All‑Sky Automated Survey for Supernovae (ASAS‑SN) has been monitoring the entire sky since 2014 with a 2–3‑day cadence to V≲17, yielding 100–500 epochs per field. The project aims to build a comprehensive variable‑star database that will soon include light curves of known variables and results from a systematic all‑sky variability survey. Candidate variables are identified during supernova searches, classified with a random‑forest algorithm and visually verified, and their V‑band light curves are made publicly available through the ASAS‑SN database. The catalog contains 66,179 newly discovered bright variables, comprising 27,479 periodic and 38,700 irregular stars.

Abstract

The All-Sky Automated Survey for Supernovae (ASAS-SN) is the first optical survey to routinely monitor the whole sky with a cadence of $\sim2-3$ days down to V$\lesssim17$ mag. ASAS-SN has monitored the whole sky since 2014, collecting $\sim100-500$ epochs of observations per field. The V-band light curves for candidate variables identified during the search for supernovae are classified using a random forest classifier and visually verified. We present a catalog of 66,179 bright, new variable stars discovered during our search for supernovae, including 27,479 periodic variables and 38,700 irregular variables. V-band light curves for the ASAS-SN variables are available through the ASAS-SN variable stars database (https://asas-sn.osu.edu/variables). The database will begin to include the light curves of known variable stars in the near future along with the results for a systematic, all-sky variability survey.