eCite Digital Repository

Microlensing discovery of a population of very tight, very low mass binary brown dwarfs


Choi, J-Y and Han, C and Udalski, A and Sumi, T and Gaudi, BS and Gould, A and Bennett, DP and Dominik, M and Beaulieu, J-P and Tsapras, Y and Bozza, V and Abe, F and Bond, IA and Botzler, CS and Chote, P and Freeman, M and Fukui, A and Furusawa, K and Itow, Y and Ling, CH and Masuda, K and Matsubara, Y and Miyake, N and Muraki, Y and Ohnishi, K and Rattenbury, NJ and Saito, T and Sullivan, DJ and Suzuki, K and Sweatman, WL and Suzuki, D and Takino, S and Tristram, PJ and Wada, K and Yock, PCM and Szymanski, MK and Kubiak, M and Pietrzynski, G and Soszynski, I and Skowron, J and Kozlowski, S and Poleski, R and Ulaczyk, K and Wyrzykowski, L and Pietrukowicz, P and Almeida, LA and DePoy, DL and Dong, S and Gorbikov, E and Jablonski, F and Henderson, CB and Hwang, K-H and Janczak, J and Jung, Y-K and Kaspi, S and Lee, C-U and Malamud, U and Maoz, D and McGregor, D and Munoz, JA and Park, B-G and Park, H and Pogge, RW and Shvartzvald, Y and Shin, I-G and Yee, JC and Alsubai, KA and Browne, P and Burgdorf, MJ and Novati, SC and Dodds, P and Fang, X-S and Finet, F and Glitrup, M and Grundahl, F and Gu, S-H and Hardis, S and Harpsoe, K and Hinse, TC and Hornstrup, A and Hundertmark, M and Jessen-Hansen, J and Jorgensen, UG and Kains, N and Kerins, E and Liebig, C and Lund, MN and Lundkvist, M and Maier, G and Mancini, L and Mathiasen, M and Penny, MT and Rahvar, S and Ricci, D and Scarpetta, G and Skottfelt, J and Snodgrass, C and Southworth, J and Surdej, J and Tregloan-Reed, J and Wambsganss, J and Wertz, O and Zimmer, F and Albrow, MD and Bachelet, E and Batista, V and Brillant, S and Cassan, A and Cole, AA and Coutures, C and Dieters, S and Prester, DD and Donatowicz, J and Fouque, P and Greenhill, J and Kubas, D and Marquette, J-B and Menzies, JW and Sahu, KC and Zub, M and Bramich, DM and Horne, K and Steele, IA and Street, RA, Microlensing discovery of a population of very tight, very low mass binary brown dwarfs, Astrophysical Journal, 768, (2) Article 129. ISSN 0004-637X (2013) [Refereed Article]

Restricted - Request a copy

Copyright Statement

Copyright 2013 The American Astronomical Society

DOI: doi:10.1088/0004-637X/768/2/129


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 and 0.034 M, 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. 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.

Item Details

Item Type:Refereed Article
Keywords:binaries: general - gravitational lensing: micro
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Cole, AA (Associate Professor Andrew Cole)
UTAS Author:Dieters, S (Dr Stefan Dieters)
UTAS Author:Greenhill, J (Dr John Greenhill)
ID Code:88393
Year Published:2013
Web of Science® Times Cited:27
Deposited By:Mathematics and Physics
Deposited On:2014-01-31
Last Modified:2017-11-06

Repository Staff Only: item control page