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Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events

Citation

Shin, I-G and Han, C and Choi, J-Y and Udalski, A and Sumi, T and Gould, A and Bozza, V and Dominik, M and Fouque, P and Horne, K and Szymanski, MK and Kubiak, M and Soszynski, I and Pietrzynski, G and Poleski, R and Ulaczyk, K and Pietrukowicz, P and Kozlowski, S and Skowron, J and Wyrzykowski, L and Abe, F and Bennett, DP and Bond, IA and Botzler, CS and Chote, P and Freeman, M and Fukui, A and Furusawa, K and Itow, Y and Kobara, S and Ling, CH and Masuda, K and Matsubara, Y and Miyake, N and Muraki, Y and Ohmori, K and Ohnishi, K and Rattenbury, NJ and Saito, To and Sullivan, DJ and Suzuki, D and Suzuki, K and Sweatman, WL and Takino, S and Tristram, PJ and Wada, K and Yock, PCM and Bramich, DM and Snodgrass, C and Steele, IA and Street, RA and Tsapras, Y and Alsubai, KA and Browne, P and Burgdorf, MJ and Calchi Novati, S and Dodds, P and Dreizler, S and Fang, X-S and Grundahl, F and Gu, C-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, M and Lunkvist, M and Mancini, L and Mathiasen, M and Penny, MT and Rahvar, S and Ricci, D and Scarpetta, G and Skottfelt, J and Southworth, J and Surdej, J and Tregloan-Reed, J and Wambsganss, J and Wetz, O and Almeida, LA and Batista, V and Christie, G and DePloy, DL and Dong, Subo and Gaudi, BS and Henderson, C and Jablonski, F and Lee, C-U and McCormick, J and McGregor, D and Moorhouse, D and Natusch, T and Ngan, H and Park, S-Y and Pogge, RW and Tan, T-G and Thornely, G and Yee, JC and Albrow, MD and Bachelet, E and Beaulieu, J-P and Brillant, S and Cassan, A and Cole, AA and Corrales, E and Coutures, C and Dieters, S and Dominis Prester, D and Donatowicz, J and Greenhill, J and Kubas, D and Marquette, J-B and Menzies, JW and Sahu, KC and Zub, M, Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events, The Astrophysical Journal, 755, (2) Article 91. ISSN 0004-637X (2012) [Refereed Article]

Copyright Statement

Copyright 2012 The American Astronomical Society

DOI: doi:10.1088/0004-637X/755/2/91

Abstract

Despite the astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar multiplicity across a broad range of physical parameters. In this paper, we report the detections and measurements of two binaries discovered from observations of microlensing events MOA-2011-BLG-090 and OGLE-2011-BLG-0417. Determinations of the binary masses are possible by simultaneously measuring the Einstein radius and the lens parallax. The measured masses of the binary components are 0.43 M and 0.39 M for MOA-2011-BLG-090 and 0.57 M and 0.17 M for OGLE-2011-BLG-0417 and thus both lens components of MOA-2011-BLG-090 and one component of OGLE-2011-BLG-0417 are M dwarfs, demonstrating the usefulness of microlensing in detecting binaries composed of low-mass components. From modeling of the light curves considering full Keplerian motion of the lens, we also measure the orbital parameters of the binaries. The blended light of OGLE-2011-BLG-0417 comes very likely from the lens itself, making it possible to check the microlensing orbital solution by follow-up radial-velocity observation. For both events, the caustic-crossing parts of the light curves, which are critical for determining the physical lens parameters, were resolved by high-cadence survey observations and thus it is expected that the number of microlensing binaries with measured physical parameters will increase in the future.

Item Details

Item Type:Refereed Article
Keywords:binaries: general; gravitational lensing: micro
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Stellar Astronomy and Planetary Systems
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Cole, AA (Dr Andrew Cole)
Author:Dieters, S (Dr Stefan Dieters)
Author:Greenhill, J (Dr John Greenhill)
ID Code:82653
Year Published:2012
Web of Science® Times Cited:15
Deposited By:Mathematics and Physics
Deposited On:2013-02-12
Last Modified:2017-11-06
Downloads:0

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