Microlensing Discovery of a Population of Very Tight, Very Low Mass Binary Brown Dwarfs

6533b884fe1ef96bd12e0219

RESEARCH PRODUCT

Microlensing Discovery of a Population of Very Tight, Very Low Mass Binary Brown Dwarfs

J.-y. Choi C. Han A. Udalski T. Sumi B. S. Gaudi A. Gould D. P. Bennett M. Dominik J.-p. Beaulieu Y. Tsapras V. Bozza J. C. Yee The μFun Collaboration K. A. Alsubai S. Calchi Novati P. Dodds X.-s. Fang F. Finet M. Glitrup F. Grundahl S.-h. Gu G. Scarpetta S. Hardis J. Southworth K. Harpsøe T. C. Hinse A. Hornstrup M. Hundertmark J. Jessen-hansen U. G. Jrgensen N. Kains E. Kerins J. Skottfelt C. Liebig M. N. Lund Jean Surdej M. Lundkvist G. Maier L. Mancini M. Mathiasen M. T. Penny S. Rahvar Davide Ricci C. Snodgrass J. Tregloan-reed J. Wambsganss Olivier Wertz F. Zimmer The Mindstep Consortium M. D. Albrow E. Bachelet I. A. Steele V. Batista F. Abe S. Brillant A. Cassan A. A. Cole C. Coutures S. Dieters D. Dominis Prester J. Donatowicz P. Fouqué R. A. Street J. Greenhill D. Kubas I. A. Bond J.-b. Marquette J. W. Menzies K. C. Sahu M. Zub The Planet Collaboration D. M. Bramich K. Horne The Robonet Collaboration C. S. Botzler P. Chote M. Freeman A. Fukui K. Furusawa Y. Itow C. H. Ling J. Skowron K. Masuda Y. Matsubara N. Miyake Y. Muraki K. Ohnishi N. J. Rattenbury To Saito D. J. Sullivan K. Suzuki W. L. Sweatman S. Kozłowski D. Suzuki S. Takino P. J. Tristram K. Wada P. C. M. Yock The Moa Collaboration M. K. Szymański M. Kubiak G. Pietrzyński I. Soszyński R. Poleski K. Ulaczyk Ł. Wyrzykowski P. Pietrukowicz The Ogle Collaboration L. A. Almeida D. L. Depoy Subo Dong P. Browne E. Gorbikov F. Jablonski C. B. Henderson K.-h. Hwang J. Janczak Y.-k. Jung S. Kaspi C.-u. Lee U. Malamud D. Maoz M. J. Burgdorf D. Mcgregor J. A. Muñoz B.-g. Park H. Park R. W. Pogge Y. Shvartzvald I.-g. Shin

subject

Aérospatiale astronomie & astrophysique binaries: general Physical chemical mathematical & earth Sciences Physique chimie mathématiques & sciences de la terre Space science astronomy & astrophysics gravitational lensing: micro

description

Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs (BDs) are poorly understood. The multiplicity properties and minimum mass of the BD mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very low mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 M [SUB]⊙[/SUB] and 0.034 M [SUB]⊙[/SUB], and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field BD binaries known. The discovery of a population of such binaries indicates that BD binaries can robustly form at least down to masses of ~0.02 M [SUB]⊙[/SUB]. Future microlensing surveys will measure a mass-selected sample of BD binary systems, which can then be directly compared to similar samples of stellar binaries.

year	journal	country	edition	language
2013-05-01

10.1088/0004-637x/768/2/129 https://doi.org/10.1088/0004-637X/768/2/129