HD_139139
HD 139139
Star system in the constellation Libra
HD 139139 (also known as EPIC 249706694) is likely part of a bound pair system of main sequence stars about 350 light-years (110 parsecs) away from Earth in the constellation Libra. HD 139139 is a G-type main-sequence star, a little larger and more luminous than the Sun, and at an almost identical temperature. It has an apparent magnitude of 9.8. The companion star is thought to be a K5-K7 red dwarf 3.3″ away from HD 139139. It is about three magnitudes fainter and has a temperature of between 4,100 and 4,300 K.[7] Both stars have a similar proper motion, meaning they may form a gravitationally-bound binary pair.
HD 139139 exhibits dips in brightness similar to those caused by transiting Earth-like planets.[7] The Kepler space telescope observed 28 dips in their brightness over an 87-day period (23 August – 20 November 2017).[8][9] The dips do not appear to be periodic as would be expected if they were due to transiting planets.[10][11][12]
It is unknown which of the two stars produces the dimming events.[7] Potential explanations that have been investigated include planets transiting a binary star, planets that are perturbing the orbits of each other producing large transit timing variations, a disintegrating planet, large dust producing asteroids, and short lived sunspots.[7][13][14] According to Andrew Vanderburg, one of the researchers of the original studies,