Characterizing Low-Mass Binaries From Observation of Long Time-scale Caustic-crossing Gravitational Microlensing Events
Abstract
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 and 0.39 for MOA-2011-BLG-090 and 0.57 and 0.17 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.
Keywords
Cite
@article{arxiv.1204.2869,
title = {Characterizing Low-Mass Binaries From Observation of Long Time-scale Caustic-crossing Gravitational Microlensing Events},
author = {I. -G. Shin and C. Han and J. -Y. Choi and A. Udalski and T. Sumi and A. Gould and V. Bozza and M. Dominik and P. Fouqué and K. Horne and M. and K. Szymański and M. Kubiak and I. Soszyński and G. Pietrzyński and R. Poleski and K. Ulaczyk and P. Pietrukowicz and S. Kozłowski and J. Skowron and Ł. Wyrzykowski and F. Abe and D. P. Bennett and I. A. Bond and C. S. Botzler and P. Chote and M. Freeman and A. Fukui and K. Furusawa and Y. Itow and S. Kobara and C. H. Ling and K. Masuda and Y. Matsubara and N. Miyake and Y. Muraki and K. Ohmori and K. Ohnishi and N. J. Rattenbury and To. Saito and D. J. Sullivan and D. Suzuki and K. Suzuki and W. L. Sweatman and S. Takino and P. J. Tristram and K. Wada and P. C. M. Yock and D. M. Bramich and C. Snodgrass and I. A. Steele and R. A. Street and Y. Tsapras and K. A. Alsubai and P. Browne and M. J. Burgdorf and S. Calchi Novati and P. Dodds and S. Dreizler and X. -S. Fang and F. Grundahl and C. -H. Gu and S. Hardis and K. Harpsøe and T. C. Hinse and A. Hornstrup and M. Hundertmark and J. Jessen-Hansen and U. G. Jørgensen and N. Kains and E. Kerins and C. Liebig and M. Lund and M. Lunkkvist and L. Mancini and M. Mathiasen and M. T. Penny and S. Rahvar and D. Ricci and G. Scarpetta and J. Skottfelt and J. Southworth and J. Surdej and J. Tregloan-Reed and J. Wambsganss and O. Wertz and L. A. Almeida and V. Batista and G. Christie and D. L. DePoy and Subo Dong and B. S. Gaudi and C. Henderson and F. Jablonski and C. -U. Lee and J. McCormick and D. McGregor and D. Moorhouse and T. Natusch and H. Ngan and S. -Y. Park and R. W. Pogge and T. -G. Tan and G. Thornley and J. C. Yee and M. D. Albrow and E. Bachelet and J. -P. Beaulieu and S. Brillant and A. Cassan and A. A. Cole and E. Corrales and C. Coutures and S. Dieters and D. Dominis Prester and J. Donatowicz and J. Greenhill and D. Kubas and J. -B. Marquette and J. W. Menzies and K. C. Sahu and M. Zub},
journal= {arXiv preprint arXiv:1204.2869},
year = {2016}
}
Comments
8 pages, 5 figures, 4 tables