The graph made astronomer Tabetha “Tabby” Boyajian sit up at her desk at Yale University. Something was definitely strange — the line was mostly flat but had two sharp dips resembling stalactites hanging from the ceiling of a cave.

The dips implied that light coming from the star KIC 8462852, more than 1,400 light years away, had dimmed twice in a most unexpected way.

The starlight graph Boyajian was looking at in the summer of 2013 is part of a large data set that the space-based Kepler telescope collected during its four-year mission to hunt for Earth-like planets around other stars. Dips in the amount of light coming from a star can indicate a planet passing in front of it. The bigger the planet, the larger the light dip. Boyajian’s graph suggested the presence of a planet more massive than any astronomer has ever seen — or maybe something stranger.

The two dimming events she observed from KIC 8462852 happened around the 800th and 1,500th days of observation, when the star’s light dropped by 15 and 22 percent, respectively. A planet the size of Jupiter, roughly 11 times the size of Earth, would cause a dip of only 1 percent — so whatever is orbiting KIC 8462852 is much bigger than the largest planet in our solar system.

Published by Science Line.  See more at: http://scienceline.org/2016/01/tabbys-mystery/