AAVSO: American Association of Variable Star Observers

A 1,574-Day Periodicity of Transits Orbiting KIC 8462852

Volume 46 number 1 (2018)

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Gary Sacco
3250 SW 195 Terrace, Miramar, FL 33029; gdsacco@hotmail.com
Linh D. Ngo
13980 W 78th Avenue, Arvada, CO 80005; linh@ngo.net
Julien Modolo
Laboratoire Traitement du Signal et de l’Image, 35042 Rennes, France; INSERM, Rennes 1 University, LTSI, Rennes, F-35000, France; julien.modolo@gmail.com

Abstract

Observations of the main sequence F3V star KIC 8462852 (also known as Boyajian’s star) revealed extreme aperiodic dips in flux up to 20% during the four years of the Kepler mission. Smaller dips (< 3%) were also observed with ground-based telescopes between May 2017 and May 2018. We investigated possible correlation between recent dips and the major dips in the last 100 days of the Kepler mission. We compared Kepler light curve data, 2017 data from two observatories (TFN, OGG) which are part of the Las Cumbres Observatory (LCO) network, as well as archival data from the Harvard College Observatory (HCO), Sonneberg Observatory, and Sternberg Observatory, and determined that observations appear consistent with a 1,574-day (4.31-year) periodicity of a transit (or group of transits) orbiting Boyajian’s star within the habitable zone. Comparison with future observations is required to validate this hypothesis. Furthermore, it is unknown if transits that have produced other major dips as observed during the Kepler mission (e.g. D792) share the same orbital period. Nevertheless, the proposed periodicity is a step forward in guiding future observation efforts.