Wednesday, April 13, 2016

Cold Giants Circling a Distant Sun

OGLE-2012-BLG-0026 is a gravitational microlensing event previously discovered by Han et al. 2013. A gravitational microlensing event occurs when a massive foreground object crosses the line-of-sight to a background star. The gravitational field of the foreground object can act as a lens and magnify the brightness of the background star. In the case of OGLE-2012-BLG-0026, the foreground object consists of a Sun-like star with two cold gas giant planets. Since its detection, the angular separation of the foreground star from the background star has increased sufficiently to allow light from the foreground star to be observed separately. As a result, new observations of the foreground star have enabled the physical parameters of the planetary system to be constrained to within 5 percent. The two gas giant planets are estimated to have 0.145 ± 0.008 and 0.86 ± 0.06 times the mass of Jupiter, and projected separations of 4.0 ± 0.5 AU and 4.8 ± 0.7 AU, respectively. Both planets are typical cold gas giant planets orbiting a Sun-like star, similar to Jupiter and Saturn.

Beaulieu et al. (2016), "Revisiting the microlensing event OGLE 2012-BLG-0026: A solar mass star with two cold giant planets", arXiv:1601.01846 [astro-ph.EP]