Microlensing Discovery of a Tight, Low Mass-ratio Planetary-mass Object around an Old, Field Brown Dwarf
Abstract
Observations of accretion disks around young brown dwarfs have led to the speculation that they may form planetary systems similar to normal stars. While there have been several detections of planetary-mass objects around brown dwarfs (2MASS 1207-3932 and 2MASS 0441-2301), these companions have relatively large mass ratios and projected separations, suggesting that they formed in a manner analogous to stellar binaries. We present the discovery of a planetary-mass object orbiting a field brown dwarf via gravitational microlensing, OGLE-2012-BLG-0358Lb. The system is a low secondary/primary mass ratio (0.080 +- 0.001), relatively tightly-separated (~0.87 AU) binary composed of a planetary-mass object with 1.9 +- 0.2 Jupiter masses orbiting a brown dwarf with a mass 0.022 M_Sun. The relatively small mass ratio and separation suggest that the companion may have formed in a protoplanetary disk around the brown dwarf host, in a manner analogous to planets.
Keywords
Cite
@article{arxiv.1307.6335,
title = {Microlensing Discovery of a Tight, Low Mass-ratio Planetary-mass Object around an Old, Field Brown Dwarf},
author = {C. Han and Y. K. Jung and A. Udalski and T. Sumi and B. S. Gaudi and A. Gould and D. P. Bennett and Y. Tsapras and M. K. Szymański and M. Kubiak and G. Pietrzyński and I. Soszyński and J. Skowron and S. Kozłowski and R. Poleski and K. Ulaczyk and Ł. Wyrzykowski and P. Pietrukowicz and F. Abe and I. A. Bond and C. S. Botzler and P. Chote and M. Freeman and A. Fukui and K. Furusawa and P. Harris and Y. Itow and C. H. Ling and K. Masuda and Y. Matsubara and Y. Muraki and K. Ohnishi and N. J. Rattenbury and To. Saito and D. J. Sullivan and W. L. Sweatman and D. Suzuki and P. J. Tristram and K. Wada and P. C. M. Yock and V. Batista and G. Christie and J. -Y. Choi and D. L. DePoy and Subo Dong and K. -H. Hwang and A. Kavka and C. -U. Lee and L. A. G. Monard and T. Natusch and H. Ngan and H. Park and R. W. Pogge and I. Porritt and I. -G. Shin and T. G. Tan and J. C. Yee and K. A. Alsubai and V. Bozza and D. M. Bramich and P. Browne and M. Dominik and K. Horne and M. Hundertmark and S. Ipatov and N. Kains and C. Liebig and C. Snodgrass and I. A. Steele and R. A. Street},
journal= {arXiv preprint arXiv:1307.6335},
year = {2015}
}
Comments
6 pages, 3 figures, 3 tables, Submitted in ApJ