An Earth-mass Planet in a 1 au Orbit around an Ultracool Dwarf

May 2017 • 2017ApJ...840L...3S

Authors • Shvartzvald, Y. • Yee, J. C. • Calchi Novati, S. • Gould, A. • Lee, C. -U. • Beichman, C. • Bryden, G. • Carey, S. • Gaudi, B. S. • Henderson, C. B. • Zhu, W. • Spitzer Team • Albrow, M. D. • Cha, S. -M. • Chung, S. -J. • Han, C. • Hwang, K. -H. • Jung, Y. K. • Kim, D. -J. • Kim, H. -W. • Kim, S. -L. • Lee, Y. • Park, B. -G. • Pogge, R. W. • Ryu, Y. -H. • Shin, I. -G. • KMTNet Group

Abstract • We combine Spitzer and ground-based Korea Microlensing Telescope Network microlensing observations to identify and precisely measure an Earth-mass ({1.43}-0.32+0.45{M}\oplus ) planet OGLE-2016-BLG-1195Lb at {1.16}-0.13+0.16 {au} orbiting a {0.078}-0.012+0.016{M} ultracool dwarf. This is the lowest-mass microlensing planet to date. At {3.91}-0.46+0.42 kpc, it is the third consecutive case among the Spitzer “Galactic distribution” planets toward the Galactic bulge that lies in the Galactic disk as opposed to the bulge itself, hinting at a skewed distribution of planets. Together with previous microlensing discoveries, the seven Earth-size planets orbiting the ultracool dwarf TRAPPIST-1, and the detection of disks around young brown dwarfs, OGLE-2016-BLG-1195Lb suggests that such planets might be common around ultracool dwarfs. It therefore sheds light on the formation of both ultracool dwarfs and planetary systems at the limit of low-mass protoplanetary disks.


IPAC Authors


Sebastiano Calchi Novati

Associate Scientist

Sean Carey

Senior Scientist