MICROLENSING BINARIES WITH CANDIDATE BROWN DWARF COMPANIONS

Journal Article · Sat Dec 01 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/760/2/116· OSTI ID:22086253

Shin, I -G; Han, C ^[1]; Gould, A; Skowron, J ^[2]; Udalski, A; Szymanski, M K; Kubiak, M; Soszynski, I; Pietrzynski, G; Poleski, R; Ulaczyk, K; Pietrukowicz, P; Kozlowski, S; Wyrzykowski, L ^[3]; Sumi, T ^[4]; Dominik, M ^[5]; Beaulieu, J -P ^[6]; Tsapras, Y ^[7]; Bozza, V ^[8]; Abe, F ^[9] ; others, and

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1. Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of)
2. Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States)
3. Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland)
4. Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan)
5. SUPA, University of St. Andrews, School of Physics and Astronomy, North Haugh, St. Andrews KY16 9SS (United Kingdom)
6. Institut d'Astrophysique de Paris, UMR7095 CNRS-Universite Pierre and Marie Curie, 98 bis boulevard Arago, F-75014 Paris (France)
7. Las Cumbres Observatory Global Telescope Network, 6740B Cortona Dr., Suite 102, Goleta, CA 93117 (United States)
8. Dipartimento di Fisica 'E. R. Caianiello', Universita degli Studi di Salerno, Via S. Allende, I-84081 Baronissi (Italy)
9. Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan)

Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing events discovered during the 2004-2011 observation seasons. Based on the low mass ratio criterion of q < 0.2, we found seven candidate events: OGLE-2004-BLG-035, OGLE-2004-BLG-039, OGLE-2007-BLG-006, OGLE-2007-BLG-399/MOA-2007-BLG-334, MOA-2011-BLG-104/OGLE-2011-BLG-0172, MOA-2011-BLG-149, and MOA-201-BLG-278/OGLE-2011-BLG-012N. Among them, we are able to confirm that the companions of the lenses of MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149 are brown dwarfs by determining the mass of the lens based on the simultaneous measurement of the Einstein radius and the lens parallax. The measured masses of the brown dwarf companions are 0.02 {+-} 0.01 M {sub Sun} and 0.019 {+-} 0.002 M {sub Sun} for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events with well-covered light curves increases with new-generation searches.

• OSTI ID: 22086253
• Journal Information: Astrophysical Journal, Vol. 760, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTRONOMY
ASTROPHYSICS
BINARY STARS
DIAGRAMS
DWARF STARS
GRAVITATIONAL LENSES
MASS
PLANETS
VISIBLE RADIATION