Tuesday, July 19, 2016

Intermediate-Mass Planet beyond the Snow Line

Koshimoto et al. (2016) present the detection of a planet identified as OGLE-2012-BLG-0950Lb. This planet and its host star crossed the line-of-sight to a background source, and the combined gravitational field of the planet and its host star generated a gravitational microlensing event. OGLE-2012-BLG-0950Lb is the first planet to be discovered solely from the gravitational microlensing parallax due to the Earth’s orbital motion around the Sun and from detection of flux from the planet's host star.

OGLE-2012-BLG-0950Lb is estimated to have ~35 times the mass of Earth and it orbits around a host star with ~0.56 times the mass of the Sun. The planet's projected distance from its host star is ~2.7 AU and the planetary system is estimated to be located ~10,000 light years away. OGLE-2012-BLG-0950Lb orbits outside the snow line of its host star and its mass is between that of Neptune and Saturn. Such intermediate-mass planets beyond the snowline are predicted to be common in the core accretion model of planet formation.

Koshimoto et al. (2016), "OGLE-2012-BLG-0950Lb: The Possible First Planet Mass Measurement from Only Microlens Parallax and Lens Flux", arXiv:1607.03267 [astro-ph.EP]