The Year-long Flux Variations in Boyajian's Star Are Asymmetric or Aperiodic

Abstract

We combine and calibrate publicly available data for Boyajian’s star, including photometry from ASAS (SN, V, I), Kepler , Gaia , SuperWASP, and citizen scientist observations (AAVSO, HAO, and Burke-Gaffney). Precise (mmag) photometry covers the years 2006–2017. We show that the year-long flux variations with an amplitude of ≈4% cannot be explained with cyclical symmetric or asymmetric models with periods shorter than 10 years. If the dips are transits, their periods must exceed 10 years, or their structure must evolve significantly during each four-year-long cycle.