Characterizing Low-Mass Binaries From Observation of Long Time-scale Caustic-crossing Gravitational Microlensing Events
Creators: name: Shin, I. -G.
name: Han, C.
name: Choi, J. -Y.
name: Udalski, A.
name: Sumi, T.
name: Gould, A.
name: Bozza, V.
name: Dominik, M.
name: Fouqué, P.
name: Horne, K.
name: M.
name: Szymański, K.
name: Kubiak, M.
name: Soszyński, I.
name: Pietrzyński, G.
name: Poleski, R.
name: Ulaczyk, K.
name: Pietrukowicz, P.
name: Kozłowski, S.
name: Skowron, J.
name: Wyrzykowski, Ł.
name: Abe, F.
name: Bennett, D. P.
name: Bond, I. A.
name: Botzler, C. S.
name: Chote, P.
name: Freeman, M.
name: Fukui, A.
name: Furusawa, K.
name: Itow, Y.
name: Kobara, S.
name: Ling, C. H.
name: Masuda, K.
name: Matsubara, Y.
name: Miyake, N.
name: Muraki, Y.
name: Ohmori, K.
name: Ohnishi, K.
name: Rattenbury, N. J.
name: Saito, To.
name: Sullivan, D. J.
name: Suzuki, D.
name: Suzuki, K.
name: Sweatman, W. L.
name: Takino, S.
name: Tristram, P. J.
name: Wada, K.
name: Yock, P. C. M.
name: Bramich, D. M.
name: Snodgrass, C.
name: Steele, I. A.
name: Street, R. A.
name: Tsapras, Y.
name: Alsubai, K. A.
name: Browne, P.
name: Burgdorf, M. J.
name: Novati, S. Calchi
name: Dodds, P.
name: Dreizler, S.
name: Fang, X. -S.
name: Grundahl, F.
name: Gu, C. -H.
name: Hardis, S.
name: Harpsøe, K.
name: Hinse, T. C.
name: Hornstrup, A.
name: Hundertmark, M.
name: Jessen-Hansen, J.
name: Jørgensen, U. G.
name: Kains, N.
name: Kerins, E.
name: Liebig, C.
name: Lund, M.
name: Lunkkvist, M.
name: Mancini, L.
name: Mathiasen, M.
name: Penny, M. T.
name: Rahvar, S.
name: Ricci, D.
name: Scarpetta, G.
name: Skottfelt, J.
name: Southworth, J.
name: Surdej, J.
name: Tregloan-Reed, J.
name: Wambsganss, J.
name: Wertz, O.
name: Almeida, L. A.
name: Batista, V.
name: Christie, G.
name: DePoy, D. L.
name: Dong, Subo
name: Gaudi, B. S.
name: Henderson, C.
name: Jablonski, F.
name: Lee, C. -U.
name: McCormick, J.
name: McGregor, D.
name: Moorhouse, D.
name: Natusch, T.
name: Ngan, H.
name: Park, S. -Y.
name: Pogge, R. W.
name: Tan, T. -G.
name: Thornley, G.
name: Yee, J. C.
name: Albrow, M. D.
name: Bachelet, E.
name: Beaulieu, J. -P.
name: Brillant, S.
name: Cassan, A.
name: Cole, A. A.
name: Corrales, E.
name: Coutures, C.
name: Dieters, S.
name: Prester, D. Dominis
name: Donatowicz, J.
name: Greenhill, J.
name: Kubas, D.
name: Marquette, J. -B.
name: Menzies, J. W.
name: Sahu, K. C.
name: Zub, M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Despite 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 2 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 $M_{\odot}$ and 0.39 $M_{\odot}$ for MOA-2011-BLG-090 and 0.57 $M_{\odot}$ and 0.17 $M_{\odot}$ 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.
description: 8 pages, 5 figures, 4 tables