Tuesday, October 11, 2016

KIC 8462852 (tabby's Star) Did not Dim Between 1934 and 1995


Hippke et al


The F3 main sequence star KIC 8462852 has raised interest because of its mysterious day-long brightness dips, and an unusual ~3% brightness decrease during the 4 years of the Kepler mission. Recently, a 0.164mag (~14%) dimming between 1890 and 1990 was claimed, based on the analysis of photographic plates, although this has been refuted. To resolve this controversy, we have gathered an independent set of historic data from Sonneberg Observatory, Germany. From these historic plates, we could extract 862 magnitudes in blue light, and 401 magnitudes in red light. The data cover the years 1934 to 1995 and are very evenly sampled between 1956 and 1995. In both colors, we find the star to be of constant brightness within 0.033mag/century (~3%). The previously claimed dimming is inconsistent with these data at the ∼5σ-level, however the recently reported modest dimming of ~3% in the Kepler data is not inconsistent with these data. We have also searched for periodicities and yearly trends in the data and find none within our limits of ~10% per year.

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