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

I. G. Shin; C. Han; J. Y. Choi; A. Udalski; T. Sumi; A. Gould; V. Bozza; M. Dominik; P. Fouqué; K. Horne; M. K. Szymański; M. Kubiak; I. Soszyński; G. Pietrzyński; R. Poleski; K. Ulaczyk; P. Pietrukowicz; S. Kozłowski; J. Skowron; Wyrzykowski; F. Abe; D. P. Bennett; I. A. Bond; C. S. Botzler; P. Chote; M. Freeman; A. Fukui; K. Furusawa; Y. Itow; S. Kobara; C. H. Ling; K. Masuda; Y. Matsubara; N. Miyake; Y. Muraki; K. Ohmori; K. Ohnishi; N. J. Rattenbury; To Saito; D. J. Sullivan; D. Suzuki; K. Suzuki; W. L. Sweatman; S. Takino; P. J. Tristram; K. Wada; P. C.M. Yock; D. M. Bramich; C. Snodgrass; I. A. Steele; R. A. Street; Y. Tsapras; K. A. Alsubai; P. Browne; M. J. Burgdorf; S. Calchi Novati; P. Dodds; S. Dreizler; X. S. Fang; F. Grundahl; C. H. Gu; S. Hardis; K. Harpsoe; T. C. Hinse; A. Hornstrup; M. Hundertmark; J. Jessen-Hansen; U. G. Jorgensen; N. Kains; E. Kerins; C. Liebig; M. Lund; M. Lunkkvist; L. Mancini; M. Mathiasen; M. T. Penny; S. Rahvar; D. Ricci; G. Scarpetta; J. Skottfelt; J. Southworth; J. Surdej; J. Tregloan-Reed; J. Wambsganss; O. Wertz; L. A. Almeida; V. Batista; G. Christie; D. L. Depoy; Subo Dong; B. S. Gaudi; C. Henderson; F. Jablonski; C. U. Lee; J. McCormick; D. McGregor; D. Moorhouse; T. Natusch; H. Ngan; S. Y. Park; R. W. Pogge; T. G. Tan; G. Thornley; J. C. Yee; M. D. Albrow; E. Bachelet; J. P. Beaulieu; S. Brillant; A. Cassan; A. A. Cole; E. Corrales; C. Coutures; S. Dieters; D. Dominis Prester; J. Donatowicz; J. Greenhill; D. Kubas; J. B. Marquette; J. W. Menzies; K. C. Sahu; And M. Zub

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

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

I. G. Shin, C. Han, J. Y. Choi, A. Udalski, T. Sumi, A. Gould, V. Bozza, M. Dominik, P. Fouqué, K. Horne, M. K. Szymański, M. Kubiak, I. Soszyński, G. Pietrzyński, R. Poleski, K. Ulaczyk, P. Pietrukowicz, S. Kozłowski, J. Skowron, WyrzykowskiF. Abe, D. P. Bennett, I. A. Bond, C. S. Botzler, P. Chote, M. Freeman, A. Fukui, K. Furusawa, Y. Itow, S. Kobara, C. H. Ling, K. Masuda, Y. Matsubara, N. Miyake, Y. Muraki, K. Ohmori, K. Ohnishi, N. J. Rattenbury, To Saito, D. J. Sullivan, D. Suzuki, K. Suzuki, W. L. Sweatman, S. Takino, P. J. Tristram, K. Wada, P. C.M. Yock, D. M. Bramich, C. Snodgrass, I. A. Steele, R. A. Street, Y. Tsapras, K. A. Alsubai, P. Browne, M. J. Burgdorf, S. Calchi Novati, P. Dodds, S. Dreizler, X. S. Fang, F. Grundahl, C. H. Gu, S. Hardis, K. Harpsoe, T. C. Hinse, A. Hornstrup, M. Hundertmark, J. Jessen-Hansen, U. G. Jorgensen, N. Kains, E. Kerins, C. Liebig, M. Lund, M. Lunkkvist, L. Mancini, M. Mathiasen, M. T. Penny, S. Rahvar, D. Ricci, G. Scarpetta, J. Skottfelt, J. Southworth, J. Surdej, J. Tregloan-Reed, J. Wambsganss, O. Wertz, L. A. Almeida, V. Batista, G. Christie, D. L. Depoy, Subo Dong, B. S. Gaudi, C. Henderson, F. Jablonski, C. U. Lee, J. McCormick, D. McGregor, D. Moorhouse, T. Natusch, H. Ngan, S. Y. Park, R. W. Pogge, T. G. Tan, G. Thornley, J. C. Yee, M. D. Albrow, E. Bachelet, J. P. Beaulieu, S. Brillant, A. Cassan, A. A. Cole, E. Corrales, C. Coutures, S. Dieters, D. Dominis Prester, J. Donatowicz, J. Greenhill, D. Kubas, J. B. Marquette, J. W. Menzies, K. C. Sahu, And M. Zub

Research output: Contribution to journal › Review article

20 Citations (Scopus)

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.

Original language	English
Article number	91
Journal	Astrophysical Journal
Volume	755
Issue number	2
DOIs	https://doi.org/10.1088/0004-637X/755/2/91
Publication status	Published - 20 Aug 2012

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Keywords

binaries: general
gravitational lensing: micro

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Cite this

Shin, I. G., Han, C., Choi, J. Y., Udalski, A., Sumi, T., Gould, A., Bozza, V., Dominik, M., Fouqué, P., Horne, K., Szymański, M. K., Kubiak, M., Soszyński, I., Pietrzyński, G., Poleski, R., Ulaczyk, K., Pietrukowicz, P., Kozłowski, S., Skowron, J., ... Zub, A. M. (2012). Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events. Astrophysical Journal, 755(2), [91]. https://doi.org/10.1088/0004-637X/755/2/91

Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events. / Shin, I. G.; Han, C.; Choi, J. Y.; Udalski, A.; Sumi, T.; Gould, A.; Bozza, V.; Dominik, M.; Fouqué, P.; Horne, K.; Szymański, M. K.; Kubiak, M.; Soszyński, I.; Pietrzyński, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozłowski, S.; Skowron, J.; Wyrzykowski; Abe, F.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Chote, P.; Freeman, M.; Fukui, A.; Furusawa, K.; Itow, Y.; Kobara, S.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Ohmori, K.; Ohnishi, K.; Rattenbury, N. J.; Saito, To; Sullivan, D. J.; Suzuki, D.; Suzuki, K.; Sweatman, W. L.; Takino, S.; Tristram, P. J.; Wada, K.; Yock, P. C.M.; Bramich, D. M.; Snodgrass, C.; Steele, I. A.; Street, R. A.; Tsapras, Y.; Alsubai, K. A.; Browne, P.; Burgdorf, M. J.; Novati, S. Calchi; Dodds, P.; Dreizler, S.; Fang, X. S.; Grundahl, F.; Gu, C. H.; Hardis, S.; Harpsoe, K.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jessen-Hansen, J.; Jorgensen, U. G.; Kains, N.; Kerins, E.; Liebig, C.; Lund, M.; Lunkkvist, M.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Wambsganss, J.; Wertz, O.; Almeida, L. A.; Batista, V.; Christie, G.; Depoy, D. L.; Dong, Subo; Gaudi, B. S.; Henderson, C.; Jablonski, F.; Lee, C. U.; McCormick, J.; McGregor, D.; Moorhouse, D.; Natusch, T.; Ngan, H.; Park, S. Y.; Pogge, R. W.; Tan, T. G.; Thornley, G.; Yee, J. C.; Albrow, M. D.; Bachelet, E.; Beaulieu, J. P.; Brillant, S.; Cassan, A.; Cole, A. A.; Corrales, E.; Coutures, C.; Dieters, S.; Prester, D. Dominis; Donatowicz, J.; Greenhill, J.; Kubas, D.; Marquette, J. B.; Menzies, J. W.; Sahu, K. C.; Zub, And M.

In: Astrophysical Journal, Vol. 755, No. 2, 91, 20.08.2012.

Research output: Contribution to journal › Review article

Shin, IG, Han, C, Choi, JY, Udalski, A, Sumi, T, Gould, A, Bozza, V, Dominik, M, Fouqué, P, Horne, K, Szymański, MK, Kubiak, M, Soszyński, I, Pietrzyński, G, Poleski, R, Ulaczyk, K, Pietrukowicz, P, Kozłowski, S, Skowron, J, Wyrzykowski, Abe, F, Bennett, DP, Bond, IA, Botzler, CS, Chote, P, Freeman, M, Fukui, A, Furusawa, K, Itow, Y, Kobara, S, Ling, CH, Masuda, K, Matsubara, Y, Miyake, N, Muraki, Y, Ohmori, K, Ohnishi, K, Rattenbury, NJ, Saito, T, Sullivan, DJ, Suzuki, D, Suzuki, K, Sweatman, WL, Takino, S, Tristram, PJ, Wada, K, Yock, PCM, Bramich, DM, Snodgrass, C, Steele, IA, Street, RA, Tsapras, Y, Alsubai, KA, Browne, P, Burgdorf, MJ, Novati, SC, Dodds, P, Dreizler, S, Fang, XS, Grundahl, F, Gu, CH, Hardis, S, Harpsoe, K, Hinse, TC, Hornstrup, A, Hundertmark, M, Jessen-Hansen, J, Jorgensen, UG, Kains, N, Kerins, E, Liebig, C, Lund, M, Lunkkvist, M, Mancini, L, Mathiasen, M, Penny, MT, Rahvar, S, Ricci, D, Scarpetta, G, Skottfelt, J, Southworth, J, Surdej, J, Tregloan-Reed, J, Wambsganss, J, Wertz, O, Almeida, LA, Batista, V, Christie, G, Depoy, DL, Dong, S, Gaudi, BS, Henderson, C, Jablonski, F, Lee, CU, McCormick, J, McGregor, D, Moorhouse, D, Natusch, T, Ngan, H, Park, SY, Pogge, RW, Tan, TG, Thornley, G, Yee, JC, Albrow, MD, Bachelet, E, Beaulieu, JP, Brillant, S, Cassan, A, Cole, AA, Corrales, E, Coutures, C, Dieters, S, Prester, DD, Donatowicz, J, Greenhill, J, Kubas, D, Marquette, JB, Menzies, JW, Sahu, KC & Zub, AM 2012, 'Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events', Astrophysical Journal, vol. 755, no. 2, 91. https://doi.org/10.1088/0004-637X/755/2/91

Shin, I. G. ; Han, C. ; Choi, J. Y. ; Udalski, A. ; Sumi, T. ; Gould, A. ; Bozza, V. ; Dominik, M. ; Fouqué, P. ; Horne, K. ; Szymański, M. K. ; Kubiak, M. ; Soszyński, I. ; Pietrzyński, G. ; Poleski, R. ; Ulaczyk, K. ; Pietrukowicz, P. ; Kozłowski, S. ; Skowron, J. ; Wyrzykowski ; Abe, F. ; Bennett, D. P. ; Bond, I. A. ; Botzler, C. S. ; Chote, P. ; Freeman, M. ; Fukui, A. ; Furusawa, K. ; Itow, Y. ; Kobara, S. ; Ling, C. H. ; Masuda, K. ; Matsubara, Y. ; Miyake, N. ; Muraki, Y. ; Ohmori, K. ; Ohnishi, K. ; Rattenbury, N. J. ; Saito, To ; Sullivan, D. J. ; Suzuki, D. ; Suzuki, K. ; Sweatman, W. L. ; Takino, S. ; Tristram, P. J. ; Wada, K. ; Yock, P. C.M. ; Bramich, D. M. ; Snodgrass, C. ; Steele, I. A. ; Street, R. A. ; Tsapras, Y. ; Alsubai, K. A. ; Browne, P. ; Burgdorf, M. J. ; Novati, S. Calchi ; Dodds, P. ; Dreizler, S. ; Fang, X. S. ; Grundahl, F. ; Gu, C. H. ; Hardis, S. ; Harpsoe, K. ; Hinse, T. C. ; Hornstrup, A. ; Hundertmark, M. ; Jessen-Hansen, J. ; Jorgensen, U. G. ; Kains, N. ; Kerins, E. ; Liebig, C. ; Lund, M. ; Lunkkvist, M. ; Mancini, L. ; Mathiasen, M. ; Penny, M. T. ; Rahvar, S. ; Ricci, D. ; Scarpetta, G. ; Skottfelt, J. ; Southworth, J. ; Surdej, J. ; Tregloan-Reed, J. ; Wambsganss, J. ; Wertz, O. ; Almeida, L. A. ; Batista, V. ; Christie, G. ; Depoy, D. L. ; Dong, Subo ; Gaudi, B. S. ; Henderson, C. ; Jablonski, F. ; Lee, C. U. ; McCormick, J. ; McGregor, D. ; Moorhouse, D. ; Natusch, T. ; Ngan, H. ; Park, S. Y. ; Pogge, R. W. ; Tan, T. G. ; Thornley, G. ; Yee, J. C. ; Albrow, M. D. ; Bachelet, E. ; Beaulieu, J. P. ; Brillant, S. ; Cassan, A. ; Cole, A. A. ; Corrales, E. ; Coutures, C. ; Dieters, S. ; Prester, D. Dominis ; Donatowicz, J. ; Greenhill, J. ; Kubas, D. ; Marquette, J. B. ; Menzies, J. W. ; Sahu, K. C. ; Zub, And M. / Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events. In: Astrophysical Journal. 2012 ; Vol. 755, No. 2.

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title = "Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events",

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.",

keywords = "binaries: general, gravitational lensing: micro",

author = "Shin, {I. G.} and C. Han and Choi, {J. Y.} and A. Udalski and T. Sumi and A. Gould and V. Bozza and M. Dominik and P. Fouqu{\'e} and K. Horne and Szyma{\'n}ski, {M. K.} and M. Kubiak and I. Soszy{\'n}ski and G. Pietrzy{\'n}ski and R. Poleski and K. Ulaczyk and P. Pietrukowicz and S. Koz{\l}owski and J. Skowron and Wyrzykowski and F. Abe and Bennett, {D. P.} and Bond, {I. A.} and Botzler, {C. S.} and P. Chote and M. Freeman and A. Fukui and K. Furusawa and Y. Itow and S. Kobara and Ling, {C. H.} and K. Masuda and Y. Matsubara and N. Miyake and Y. Muraki and K. Ohmori and K. Ohnishi and Rattenbury, {N. J.} and To Saito and Sullivan, {D. J.} and D. Suzuki and K. Suzuki and Sweatman, {W. L.} and S. Takino and Tristram, {P. J.} and K. Wada and Yock, {P. C.M.} and Bramich, {D. M.} and C. Snodgrass and Steele, {I. A.} and Street, {R. A.} and Y. Tsapras and Alsubai, {K. A.} and P. Browne and Burgdorf, {M. J.} and Novati, {S. Calchi} and P. Dodds and S. Dreizler and Fang, {X. S.} and F. Grundahl and Gu, {C. H.} and S. Hardis and K. Harpsoe and Hinse, {T. C.} and A. Hornstrup and M. Hundertmark and J. Jessen-Hansen and Jorgensen, {U. G.} and N. Kains and E. Kerins and C. Liebig and M. Lund and M. Lunkkvist and L. Mancini and M. Mathiasen and Penny, {M. T.} 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 Almeida, {L. A.} and V. Batista and G. Christie and Depoy, {D. L.} and Subo Dong and Gaudi, {B. S.} and C. Henderson and F. Jablonski and Lee, {C. U.} and J. McCormick and D. McGregor and D. Moorhouse and T. Natusch and H. Ngan and Park, {S. Y.} and Pogge, {R. W.} and Tan, {T. G.} and G. Thornley and Yee, {J. C.} and Albrow, {M. D.} and E. Bachelet and Beaulieu, {J. P.} and S. Brillant and A. Cassan and Cole, {A. A.} and E. Corrales and C. Coutures and S. Dieters and Prester, {D. Dominis} and J. Donatowicz and J. Greenhill and D. Kubas and Marquette, {J. B.} and Menzies, {J. W.} and Sahu, {K. C.} and Zub, {And M.}",

year = "2012",

month = aug,

day = "20",

doi = "10.1088/0004-637X/755/2/91",

language = "English",

volume = "755",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "IOP Publishing Ltd.",

number = "2",

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TY - JOUR

T1 - Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events

AU - Shin, I. G.

AU - Han, C.

AU - Choi, J. Y.

AU - Udalski, A.

AU - Sumi, T.

AU - Gould, A.

AU - Bozza, V.

AU - Dominik, M.

AU - Fouqué, P.

AU - Horne, K.

AU - Szymański, M. K.

AU - Kubiak, M.

AU - Soszyński, I.

AU - Pietrzyński, G.

AU - Poleski, R.

AU - Ulaczyk, K.

AU - Pietrukowicz, P.

AU - Kozłowski, S.

AU - Skowron, J.

AU - Wyrzykowski,

AU - Abe, F.

AU - Bennett, D. P.

AU - Bond, I. A.

AU - Botzler, C. S.

AU - Chote, P.

AU - Freeman, M.

AU - Fukui, A.

AU - Furusawa, K.

AU - Itow, Y.

AU - Kobara, S.

AU - Ling, C. H.

AU - Masuda, K.

AU - Matsubara, Y.

AU - Miyake, N.

AU - Muraki, Y.

AU - Ohmori, K.

AU - Ohnishi, K.

AU - Rattenbury, N. J.

AU - Saito, To

AU - Sullivan, D. J.

AU - Suzuki, D.

AU - Suzuki, K.

AU - Sweatman, W. L.

AU - Takino, S.

AU - Tristram, P. J.

AU - Wada, K.

AU - Yock, P. C.M.

AU - Bramich, D. M.

AU - Snodgrass, C.

AU - Steele, I. A.

AU - Street, R. A.

AU - Tsapras, Y.

AU - Alsubai, K. A.

AU - Browne, P.

AU - Burgdorf, M. J.

AU - Novati, S. Calchi

AU - Dodds, P.

AU - Dreizler, S.

AU - Fang, X. S.

AU - Grundahl, F.

AU - Gu, C. H.

AU - Hardis, S.

AU - Harpsoe, K.

AU - Hinse, T. C.

AU - Hornstrup, A.

AU - Hundertmark, M.

AU - Jessen-Hansen, J.

AU - Jorgensen, U. G.

AU - Kains, N.

AU - Kerins, E.

AU - Liebig, C.

AU - Lund, M.

AU - Lunkkvist, M.

AU - Mancini, L.

AU - Mathiasen, M.

AU - Penny, M. T.

AU - Rahvar, S.

AU - Ricci, D.

AU - Scarpetta, G.

AU - Skottfelt, J.

AU - Southworth, J.

AU - Surdej, J.

AU - Tregloan-Reed, J.

AU - Wambsganss, J.

AU - Wertz, O.

AU - Almeida, L. A.

AU - Batista, V.

AU - Christie, G.

AU - Depoy, D. L.

AU - Dong, Subo

AU - Gaudi, B. S.

AU - Henderson, C.

AU - Jablonski, F.

AU - Lee, C. U.

AU - McCormick, J.

AU - McGregor, D.

AU - Moorhouse, D.

AU - Natusch, T.

AU - Ngan, H.

AU - Park, S. Y.

AU - Pogge, R. W.

AU - Tan, T. G.

AU - Thornley, G.

AU - Yee, J. C.

AU - Albrow, M. D.

AU - Bachelet, E.

AU - Beaulieu, J. P.

AU - Brillant, S.

AU - Cassan, A.

AU - Cole, A. A.

AU - Corrales, E.

AU - Coutures, C.

AU - Dieters, S.

AU - Prester, D. Dominis

AU - Donatowicz, J.

AU - Greenhill, J.

AU - Kubas, D.

AU - Marquette, J. B.

AU - Menzies, J. W.

AU - Sahu, K. C.

AU - Zub, And M.

PY - 2012/8/20

Y1 - 2012/8/20

N2 - 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.

AB - 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.

KW - binaries: general

KW - gravitational lensing: micro

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UR - http://www.scopus.com/inward/citedby.url?scp=84864691489&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/755/2/91

DO - 10.1088/0004-637X/755/2/91

M3 - Review article

AN - SCOPUS:84864691489

VL - 755

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 91

ER -

Access to Document

10.1088/0004-637X/755/2/91