[en] 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 [SUB]&sun;[/SUB] and 0.39 M [SUB]&sun;[/SUB] for MOA-2011-BLG-090 and 0.57 M [SUB]&sun;[/SUB] and 0.17 M [SUB]&sun;[/SUB] 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.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Shin, I.-G.; Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763, Republic of Korea ; The μFUN Collaboration.
Han, C.; Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763, Republic of Korea ; The μFUN Collaboration. ; Author.
Choi, J.-Y.; Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763, Republic of Korea ; The μFUN Collaboration.
Udalski, A.; Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland ; The OGLE Collaboration.
Sumi, T.; Department of Earth and Space Science, Osaka University, Osaka 560-0043, Japan ; The MOA Collaboration.
Gould, A.; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA ; The μFUN Collaboration.
Bozza, V.; Dipartimento di Fisica "E.R. Caianiello," Università degli Studi di Salerno, Via S. Allende, 84081 Baronissi (SA), Italy ; INFN, Gruppo Collegato di Salerno, Sezione di Napoli, Italy ; The MiNDSTEp Collaboration.
Dominik, M.; SUPA, School of Physics & Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, UK ; The MiNDSTEp Collaboration. ; Royal Society University Research Fellow.
Fouqué, P.; IRAP, Université de Toulouse, CNRS, 14 Avenue Edouard Belin, 31400 Toulouse, France ; The PLANET Collaboration.
Horne, K.; SUPA, School of Physics & Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, UK ; The RoboNet Collaboration.
Szymański, M. K.; Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
Liebig, C.; SUPA, School of Physics & Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, UK
Lund, M.; Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Århus C, Denmark
Lunkkvist, M.; Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Århus C, Denmark
Mancini, L.; Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
Mathiasen, M.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, 2100 Copenhagen, Denmark
Penny, M. T.; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA ; Jodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, Manchester M13 9PL, UK
Rahvar, S.; Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran ; Perimeter Institue for Theoretical Physics, 31 Caroline St. N., Waterloo, ON N2L2Y5, Canada
Ricci, Davide ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Scarpetta, G.; Dipartimento di Fisica "E.R. Caianiello," Università degli Studi di Salerno, Via S. Allende, 84081 Baronissi (SA), Italy ; INFN, Gruppo Collegato di Salerno, Sezione di Napoli, Italy
Skottfelt, J.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, 2100 Copenhagen, Denmark
Moorhouse, D.; Kumeu Observatory, Kumeu, New Zealand
Southworth, J.; Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK
Surdej, Jean ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Tregloan-Reed, J.; Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK
Wambsganss, J.; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), Mönchhofstr. 12-14, 69120 Heidelberg, Germany
Wertz, Olivier ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
MiNDSTEp Consortium, The
Almeida, L. A.; Instituto Nacional de Pesquisas Espaciais, São José dos Campos, SP, Brazil
Batista, V.; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA
Christie, G.; Auckland Observatory, Auckland, New Zealand
DePoy, D. L.; Department of Physics, Texas A&M University, College Station, TX, USA
Natusch, T.; Auckland Observatory, Auckland, New Zealand ; AUT University, Auckland, New Zealand
Dong, Subo; Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540, USA
Gaudi, B. S.; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA
Henderson, C.; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA
Jablonski, F.; Instituto Nacional de Pesquisas Espaciais, São José dos Campos, SP, Brazil
Lee, C.-U.; Korea Astronomy and Space Science Institute, 776 Daedukdae-ro, Yuseong-gu, Daejeon 305-348, Republic of Korea
McCormick, J.; Farm Cove Observatory, Centre for Backyard Astrophysics, Pakuranga, Auckland, New Zealand
McGregor, D.; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA
Ngan, H.; Auckland Observatory, Auckland, New Zealand
Park, S.-Y.; Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763, Republic of Korea
Pogge, R. W.; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA
Tan, T.-G.; Perth Exoplanet Survey Telescope, Perth, Australia
Thornley, G.; Kumeu Observatory, Kumeu, New Zealand
Yee, J. C.; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA
The μFUN Collaboration
Albrow, M. D.; Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8020, New Zealand
Kubiak, M.; Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
Bachelet, E.; IRAP, Université de Toulouse, CNRS, 14 Avenue Edouard Belin, 31400 Toulouse, France
Beaulieu, J.-P.; UPMC-CNRS, UMR 7095, Institut d'Astrophysique de Paris, 98bis boulevard Arago, F-75014 Paris, France
Greenhill, J.; School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, TAS 7001, Australia
Kubas, D.; UPMC-CNRS, UMR 7095, Institut d'Astrophysique de Paris, 98bis boulevard Arago, F-75014 Paris, France ; European Southern Observatory, Casilla 19001, Vitacura 19, Santiago, Chile
Marquette, J.-B.; UPMC-CNRS, UMR 7095, Institut d'Astrophysique de Paris, 98bis boulevard Arago, F-75014 Paris, France
Menzies, J. W.; South African Astronomical Observatory, P.O. Box 9, Observatory 7925, South Africa
Sahu, K. C.; Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
Zub, M.; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), Mönchhofstr. 12-14, 69120 Heidelberg, Germany
The PLANET Collaboration; )
Pietrzyński, G.; Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland ; Departamento de Astronomia, Universidad de Concepción, Casilla 160-C, Concepción, Chile
Skowron, J.; Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA
Wyrzykowski, Ł.; Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland ; Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
The OGLE Collaboration
Abe, F.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Bennett, D. P.; Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670, USA
Bond, I. A.; Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland, New Zealand
Botzler, C. S.; Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001, New Zealand
Chote, P.; School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 60, Wellington, New Zealand
Freeman, M.; Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001, New Zealand
Fukui, A.; Okayama Astrophysical Observatory, NAOJ, Okayama 719-0232, Japan
Furusawa, K.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Itow, Y.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Kobara, S.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Ling, C. H.; Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland, New Zealand
Masuda, K.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Matsubara, Y.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Miyake, N.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Muraki, Y.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Ohmori, K.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Ohnishi, K.; Nagano National College of Technology, Nagano 381-8550, Japan
Rattenbury, N. J.; Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001, New Zealand
Saito, To; Tokyo Metropolitan College of Aeronautics, Tokyo 116-8523, Japan
Sullivan, D. J.; School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 60, Wellington, New Zealand
Suzuki, D.; Department of Earth and Space Science, Osaka University, Osaka 560-0043, Japan
Suzuki, K.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Sweatman, W. L.; Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland, New Zealand
Takino, S.; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601, Japan
Tristram, P. J.; School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 60, Wellington, New Zealand
Wada, K.; Department of Earth and Space Science, Osaka University, Osaka 560-0043, Japan
Yock, P. C. M.; Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001, New Zealand
The MOA Collaboration
Bramich, D. M.; European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
Snodgrass, C.; Max Planck Institute for Solar System Research, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany
Steele, I. A.; Astrophysics Research Institute, Liverpool John Moores University, Liverpool CH41 1LD, UK
Street, R. A.; Las Cumbres Observatory Global Telescope Network, 6740B Cortona Dr, Goleta, CA 93117, USA
Tsapras, Y.; Las Cumbres Observatory Global Telescope Network, 6740B Cortona Dr, Goleta, CA 93117, USA ; School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS, UK
The RoboNet Collaboration
Alsubai, K. A.; Qatar Foundation, P.O. Box 5825, Doha, Qatar
Browne, P.; SUPA, School of Physics & Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, UK
Burgdorf, M. J.; Deutsches SOFIA Institut, Universität Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart, Germany ; SOFIA Science Center, NASA Ames Research Center, Mail Stop N211-3, Moffett Field, CA 94035, USA
Calchi Novati, S.; Dipartimento di Fisica "E.R. Caianiello," Università degli Studi di Salerno, Via S. Allende, 84081 Baronissi (SA), Italy ; Istituto Internazionale per gli Alti Studi Scientifici (IIASS), Vietri Sul Mare (SA), Italy
Dodds, P.; SUPA, School of Physics & Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, UK
Fang, X.-S.; National Astronomical Observatories/Yunnan Observatory, Joint Laboratory for Optical Astronomy, Chinese Academy of Sciences, Kunming 650011, People's Republic of China
Grundahl, F.; Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Århus C, Denmark
Gu, C.-H.; National Astronomical Observatories/Yunnan Observatory, Joint Laboratory for Optical Astronomy, Chinese Academy of Sciences, Kunming 650011, People's Republic of China
Hardis, S.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, 2100 Copenhagen, Denmark
Harpsøe, K.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, 2100 Copenhagen, Denmark ; Centre for Star and Planet Formation, Geological Museum, Øster Voldgade 5, 1350 Copenhagen, Denmark
Hinse, T. C.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, 2100 Copenhagen, Denmark ; Armagh Observatory, College Hill, Armagh BT61 9DG, UK ; Korea Astronomy and Space Science Institute, 776 Daedukdae-ro, Yuseong-gu, Daejeon 305-348, Republic of Korea
Hornstrup, A.; Institut for Rumforskning og-teknologi, Danmarks Tekniske Universitet, Juliane Maries Vej 30, 2100 København, Denmark
Hundertmark, M.; SUPA, School of Physics & Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, UK ; Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
Jessen-Hansen, J.; Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Århus C, Denmark
Jørgensen, U. G.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, 2100 Copenhagen, Denmark ; Centre for Star and Planet Formation, Geological Museum, Øster Voldgade 5, 1350 Copenhagen, Denmark
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