Variability Properties of 4 Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey
Abstract
The Kilodegree Extremely Little Telescope (KELT) has been surveying more than 70\% of the celestial sphere for nearly a decade. While the primary science goal of the survey is the discovery of transiting, large-radii planets around bright host stars, the survey has collected more than 106 images, with a typical cadence between 10-30 minutes, for more than 4 million sources with apparent visual magnitudes in the approximate range 7<V<13. Here we provide a catalog of 52,741 objects showing significant large-amplitude fluctuations likely caused by stellar variability and 62,229 objects identified with likely stellar rotation periods. The detected variability ranges in rms-amplitude from 3 mmag to 2.3 mag, and the detected periods range from 0.1 days to 2000 days. We provide variability upper limits for all other 4 million sources. These upper limits are principally a function of stellar brightness, but we achieve typical 1σ sensitivity on 30-minute timescales down to 5 mmag at V 8, and down to 43 mmag at V 13. We have matched our catalog to the TESS Input catalog and the AAVSO Variable Star Index to precipitate the follow up and classification of each source. The catalog is maintained as a living database on the Filtergraph visualization portal at the URL https://filtergraph.com/kelt\vars