A brown dwarf orbiting an M-dwarf: MOA 2009-BLG-411L

E. Bachelet; P. Fouqué; C. Han; A. Gould; M. D. Albrow; J. P. Beaulieu; E. Bertin; I. A. Bond; G. W. Christie; D. Heyrovský; K. Horne; U. G. Jørgensen; D. Maoz; M. Mathiasen; N. Matsunaga; J. McCormick; J. Menzies; D. Nataf; T. Natusch; N. Oi; N. Renon; Y. Tsapras; A. Udalski; J. C. Yee; V. Batista; D. P. Bennett; S. Brillant; J. A.R. Caldwell; A. Cassan; A. Cole; K. H. Cook; C. Coutures; S. Dieters; M. Dominik; D. Dominis Prester; J. Donatowicz; J. Greenhill; N. Kains; S. R. Kane; J. B. Marquette; R. Martin; K. R. Pollard; K. C. Sahu; R. A. Street; J. Wambsganss; A. Williams; M. Zub; M. Bos; Subo Dong; J. Drummond; B. S. Gaudi; D. Graff; J. Janczak; S. Kaspi; S. Kozłowski; C. U. Lee; L. A.G. Monard; J. A. Muñoz; B. G. Park; R. W. Pogge; D. Polishook; A. Shporer; F. Abe; C. S. Botzler; A. Fukui; K. Furusawa; J. B. Hearnshaw; Y. Itow; A. V. Korpela; C. H. Ling; K. Masuda; Y. Matsubara; N. Miyake; Y. Muraki; K. Ohnishi; N. J. Rattenbury; To Saito; D. Sullivan; T. Sumi; D. Suzuki; W. L. Sweatman; P. J. Tristram; K. Wada; A. Allan; M. F. Bode; D. M. Bramich; N. Clay; S. N. Fraser; E. Hawkins; E. Kerins; T. A. Lister; C. J. Mottram; E. S. Saunders; C. Snodgrass; I. A. Steele; P. J. Wheatley; V. Bozza; P. Browne; M. J. Burgdorf; S. Calchi Novati; S. Dreizler; F. Finet; M. Glitrup; F. Grundahl; K. Harpsøe; F. V. Hessman; T. C. Hinse; M. Hundertmark; C. Liebig; G. Maier; L. Mancini; S. Rahvar; D. Ricci; G. Scarpetta; J. Skottfelt; J. Southworth; J. Surdej; F. Zimmer

doi:10.1051/0004-6361/201219765

A brown dwarf orbiting an M-dwarf: MOA 2009-BLG-411L

E. Bachelet, P. Fouqué, C. Han, A. Gould, M. D. Albrow, J. P. Beaulieu, E. Bertin, I. A. Bond, G. W. Christie, D. Heyrovský, K. Horne, U. G. Jørgensen, D. Maoz, M. Mathiasen, N. Matsunaga, J. McCormick, J. Menzies, D. Nataf, T. Natusch, N. OiN. Renon, Y. Tsapras, A. Udalski, J. C. Yee, V. Batista, D. P. Bennett, S. Brillant, J. A.R. Caldwell, A. Cassan, A. Cole, K. H. Cook, C. Coutures, S. Dieters, M. Dominik, D. Dominis Prester, J. Donatowicz, J. Greenhill, N. Kains, S. R. Kane, J. B. Marquette, R. Martin, K. R. Pollard, K. C. Sahu, R. A. Street, J. Wambsganss, A. Williams, M. Zub, M. Bos, Subo Dong, J. Drummond, B. S. Gaudi, D. Graff, J. Janczak, S. Kaspi, S. Kozłowski, C. U. Lee, L. A.G. Monard, J. A. Muñoz, B. G. Park, R. W. Pogge, D. Polishook, A. Shporer, F. Abe, C. S. Botzler, A. Fukui, K. Furusawa, J. B. Hearnshaw, Y. Itow, A. V. Korpela, C. H. Ling, K. Masuda, Y. Matsubara, N. Miyake, Y. Muraki, K. Ohnishi, N. J. Rattenbury, To Saito, D. Sullivan, T. Sumi, D. Suzuki, W. L. Sweatman, P. J. Tristram, K. Wada, A. Allan, M. F. Bode, D. M. Bramich, N. Clay, S. N. Fraser, E. Hawkins, E. Kerins, T. A. Lister, C. J. Mottram, E. S. Saunders, C. Snodgrass, I. A. Steele, P. J. Wheatley, V. Bozza, P. Browne, M. J. Burgdorf, S. Calchi Novati, S. Dreizler, F. Finet, M. Glitrup, F. Grundahl, K. Harpsøe, F. V. Hessman, T. C. Hinse, M. Hundertmark, C. Liebig, G. Maier, L. Mancini, S. Rahvar, D. Ricci, G. Scarpetta, J. Skottfelt, J. Southworth, J. Surdej, F. Zimmer

School of Physics and Astronomy

Tel Aviv University

Research output: Contribution to journal › Article › peer-review

Abstract

Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted. Aims. MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration. Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit. Methods. Thanks to observations by all the collaborations, this event was well monitored. We first decided to characterize the source star properties by using a more refined method than the classical one: we measure the interstellar absorption along the line of sight in five different passbands (VIJHK). Secondly, we model the lightcurve by using the standard technique: make (s,q,α) grids to look for local minima and refine the results by using a downhill method (Markov chain Monte Carlo). Finally, we use a Galactic model to estimate the physical properties of the lens components. Results. We find that the source star is a giant G star with radius 9 R _·. The grid search gives two local minima, which correspond to the theoretical degeneracy s s^-1. We find that the lens is composed of a brown dwarf secondary of mass M_S = 0.05 M_· orbiting a primary M-star of mass M_P = 0.18 M_·. We also reveal a new mass-ratio degeneracy for the central caustics of close binaries. Conclusions. As far as we are aware, this is the first detection using the microlensing technique of a binary system in our Galaxy composed of an M-star and a brown dwarf.

Original language	English
Article number	A55
Journal	Astronomy and Astrophysics
Volume	547
DOIs	https://doi.org/10.1051/0004-6361/201219765
State	Published - 2012

Keywords

Binaries: general
Gravitational lensing: micro
Stars: individual: MOA 2009-BLG-411L

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Access to Document

10.1051/0004-6361/201219765

Cite this

Bachelet, E., Fouqué, P., Han, C., Gould, A., Albrow, M. D., Beaulieu, J. P., Bertin, E., Bond, I. A., Christie, G. W., Heyrovský, D., Horne, K., Jørgensen, U. G., Maoz, D., Mathiasen, M., Matsunaga, N., McCormick, J., Menzies, J., Nataf, D., Natusch, T., ... Zimmer, F. (2012). A brown dwarf orbiting an M-dwarf: MOA 2009-BLG-411L. Astronomy and Astrophysics, 547, Article A55. https://doi.org/10.1051/0004-6361/201219765

@article{550ff21254a0438fb18654085fe2ea94,

title = "A brown dwarf orbiting an M-dwarf: MOA 2009-BLG-411L",

abstract = "Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted. Aims. MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration. Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit. Methods. Thanks to observations by all the collaborations, this event was well monitored. We first decided to characterize the source star properties by using a more refined method than the classical one: we measure the interstellar absorption along the line of sight in five different passbands (VIJHK). Secondly, we model the lightcurve by using the standard technique: make (s,q,α) grids to look for local minima and refine the results by using a downhill method (Markov chain Monte Carlo). Finally, we use a Galactic model to estimate the physical properties of the lens components. Results. We find that the source star is a giant G star with radius 9 R ·. The grid search gives two local minima, which correspond to the theoretical degeneracy s s-1. We find that the lens is composed of a brown dwarf secondary of mass MS = 0.05 M· orbiting a primary M-star of mass MP = 0.18 M·. We also reveal a new mass-ratio degeneracy for the central caustics of close binaries. Conclusions. As far as we are aware, this is the first detection using the microlensing technique of a binary system in our Galaxy composed of an M-star and a brown dwarf.",

keywords = "Binaries: general, Gravitational lensing: micro, Stars: individual: MOA 2009-BLG-411L",

author = "E. Bachelet and P. Fouqu{\'e} and C. Han and A. Gould and Albrow, {M. D.} and Beaulieu, {J. P.} and E. Bertin and Bond, {I. A.} and Christie, {G. W.} and D. Heyrovsk{\'y} and K. Horne and J{\o}rgensen, {U. G.} and D. Maoz and M. Mathiasen and N. Matsunaga and J. McCormick and J. Menzies and D. Nataf and T. Natusch and N. Oi and N. Renon and Y. Tsapras and A. Udalski and Yee, {J. C.} and V. Batista and Bennett, {D. P.} and S. Brillant and Caldwell, {J. A.R.} and A. Cassan and A. Cole and Cook, {K. H.} and C. Coutures and S. Dieters and M. Dominik and {Dominis Prester}, D. and J. Donatowicz and J. Greenhill and N. Kains and Kane, {S. R.} and Marquette, {J. B.} and R. Martin and Pollard, {K. R.} and Sahu, {K. C.} and Street, {R. A.} and J. Wambsganss and A. Williams and M. Zub and M. Bos and Subo Dong and J. Drummond and Gaudi, {B. S.} and D. Graff and J. Janczak and S. Kaspi and S. Koz{\l}owski and Lee, {C. U.} and Monard, {L. A.G.} and Mu{\~n}oz, {J. A.} and Park, {B. G.} and Pogge, {R. W.} and D. Polishook and A. Shporer and F. Abe and Botzler, {C. S.} and A. Fukui and K. Furusawa and Hearnshaw, {J. B.} and Y. Itow and Korpela, {A. V.} and Ling, {C. H.} and K. Masuda and Y. Matsubara and N. Miyake and Y. Muraki and K. Ohnishi and Rattenbury, {N. J.} and To Saito and D. Sullivan and T. Sumi and D. Suzuki and Sweatman, {W. L.} and Tristram, {P. J.} and K. Wada and A. Allan and Bode, {M. F.} and Bramich, {D. M.} and N. Clay and Fraser, {S. N.} and E. Hawkins and E. Kerins and Lister, {T. A.} and Mottram, {C. J.} and Saunders, {E. S.} and C. Snodgrass and Steele, {I. A.} and Wheatley, {P. J.} and V. Bozza and P. Browne and Burgdorf, {M. J.} and {Calchi Novati}, S. and S. Dreizler and F. Finet and M. Glitrup and F. Grundahl and K. Harps{\o}e and Hessman, {F. V.} and Hinse, {T. C.} and M. Hundertmark and C. Liebig and G. Maier and L. Mancini and S. Rahvar and D. Ricci and G. Scarpetta and J. Skottfelt and J. Southworth and J. Surdej and F. Zimmer",

note = "Funding Information: We are very grateful to the observatories that support our science (Bronberg, Canopus, CTIO, ESO, IRSF, LCOGT, Liverpool, LOAO, MOA, OGLE, Perth, SAAO, Skinakas) via the generous allocation of time that makes this work possible. The operation of Canopus Observatory is in part supported by a financial contribution from David Warren. Allocation of the Holmes grant from the French Agence Nationale de la Recherche has been indispensable to finance observing trips and travel costs for meetings, and is gratefully acknowledged here. D.H. was supported by Czech Science Foundation grant GACR 205/07/0824 and by the Czech Ministry of Education project MSM0021620860. C.H. was supported by the grant 2009-0081561 of National Research Foundation of Korea. T.C.H. was financed for his astronomical research at the Armagh Observatory by the Department for Culture, Arts and Leisure, Northern Ireland, UK and is now supported by the Korea Research Council for Fundamental Science and Technology (KRCF) via the Young Scientist Research Fellowship Program. MOA project was funded by JSPS18253002 and JSPS20340052. T.S. was funded by JSPS20740104. D.R. and J.S. acknowledge support from the Communaut{\'e} fran{\c c}aise de Belgique – Actions de recherche concert{\'e}es – Acad{\'e}mie universitaire Wallonie-Europe. P.F. wishes to thank Noriyuki Matsunaga for discussions about the interplay between adopted distance and derived extinction. The research leading to these results has received funding from the European Community{\textquoteright}s Seventh Framework Programme (/FP7/2007-2013/) under grant agreement No 229517. A. Gould acknowledges support from NSF AST-1103471. B. S. Gaudi, A. Gould, and R. W. Pogge acknowledge support from NASA grant NNG04GL51G. Work by J. C. Yee is supported by a National Science Foundation Graduate Research Fellowship under Grant No. 2009068160. Work by S. Dong was performed under contract with the California Institute of Technology (Caltech) funded by NASA through the Sagan Fellowship Program. The RoboNet team is supported by the Qatar Foundation through QNRF grant NPRP-09-476-1-78. CUL acknowledges support by Korea Astronomy and Space Science Institute (KASI) grant 2012-1-410-02. This publication makes use of data products from the 2MASS project, as well as the SIMBAD database, Aladin and Vizier catalogue operation tools (CDS Strasbourg, France). The Two Micron All Sky Survey is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This work was granted access to the HPC resources of CALMIP under the allocation 2012-[1131].",

year = "2012",

doi = "10.1051/0004-6361/201219765",

language = "الإنجليزيّة",

volume = "547",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

}

Bachelet, E, Fouqué, P, Han, C, Gould, A, Albrow, MD, Beaulieu, JP, Bertin, E, Bond, IA, Christie, GW, Heyrovský, D, Horne, K, Jørgensen, UG, Maoz, D, Mathiasen, M, Matsunaga, N, McCormick, J, Menzies, J, Nataf, D, Natusch, T, Oi, N, Renon, N, Tsapras, Y, Udalski, A, Yee, JC, Batista, V, Bennett, DP, Brillant, S, Caldwell, JAR, Cassan, A, Cole, A, Cook, KH, Coutures, C, Dieters, S, Dominik, M, Dominis Prester, D, Donatowicz, J, Greenhill, J, Kains, N, Kane, SR, Marquette, JB, Martin, R, Pollard, KR, Sahu, KC, Street, RA, Wambsganss, J, Williams, A, Zub, M, Bos, M, Dong, S, Drummond, J, Gaudi, BS, Graff, D, Janczak, J, Kaspi, S, Kozłowski, S, Lee, CU, Monard, LAG, Muñoz, JA, Park, BG, Pogge, RW, Polishook, D, Shporer, A, Abe, F, Botzler, CS, Fukui, A, Furusawa, K, Hearnshaw, JB, Itow, Y, Korpela, AV, Ling, CH, Masuda, K, Matsubara, Y, Miyake, N, Muraki, Y, Ohnishi, K, Rattenbury, NJ, Saito, T, Sullivan, D, Sumi, T, Suzuki, D, Sweatman, WL, Tristram, PJ, Wada, K, Allan, A, Bode, MF, Bramich, DM, Clay, N, Fraser, SN, Hawkins, E, Kerins, E, Lister, TA, Mottram, CJ, Saunders, ES, Snodgrass, C, Steele, IA, Wheatley, PJ, Bozza, V, Browne, P, Burgdorf, MJ, Calchi Novati, S, Dreizler, S, Finet, F, Glitrup, M, Grundahl, F, Harpsøe, K, Hessman, FV, Hinse, TC, Hundertmark, M, Liebig, C, Maier, G, Mancini, L, Rahvar, S, Ricci, D, Scarpetta, G, Skottfelt, J, Southworth, J, Surdej, J & Zimmer, F 2012, 'A brown dwarf orbiting an M-dwarf: MOA 2009-BLG-411L', Astronomy and Astrophysics, vol. 547, A55. https://doi.org/10.1051/0004-6361/201219765

TY - JOUR

T1 - A brown dwarf orbiting an M-dwarf

T2 - MOA 2009-BLG-411L

AU - Bachelet, E.

AU - Fouqué, P.

AU - Han, C.

AU - Gould, A.

AU - Albrow, M. D.

AU - Beaulieu, J. P.

AU - Bertin, E.

AU - Bond, I. A.

AU - Christie, G. W.

AU - Heyrovský, D.

AU - Horne, K.

AU - Jørgensen, U. G.

AU - Maoz, D.

AU - Mathiasen, M.

AU - Matsunaga, N.

AU - McCormick, J.

AU - Menzies, J.

AU - Nataf, D.

AU - Natusch, T.

AU - Oi, N.

AU - Renon, N.

AU - Tsapras, Y.

AU - Udalski, A.

AU - Yee, J. C.

AU - Batista, V.

AU - Bennett, D. P.

AU - Brillant, S.

AU - Caldwell, J. A.R.

AU - Cassan, A.

AU - Cole, A.

AU - Cook, K. H.

AU - Coutures, C.

AU - Dieters, S.

AU - Dominik, M.

AU - Dominis Prester, D.

AU - Donatowicz, J.

AU - Greenhill, J.

AU - Kains, N.

AU - Kane, S. R.

AU - Marquette, J. B.

AU - Martin, R.

AU - Pollard, K. R.

AU - Sahu, K. C.

AU - Street, R. A.

AU - Wambsganss, J.

AU - Williams, A.

AU - Zub, M.

AU - Bos, M.

AU - Dong, Subo

AU - Drummond, J.

AU - Gaudi, B. S.

AU - Graff, D.

AU - Janczak, J.

AU - Kaspi, S.

AU - Kozłowski, S.

AU - Lee, C. U.

AU - Monard, L. A.G.

AU - Muñoz, J. A.

AU - Park, B. G.

AU - Pogge, R. W.

AU - Polishook, D.

AU - Shporer, A.

AU - Abe, F.

AU - Botzler, C. S.

AU - Fukui, A.

AU - Furusawa, K.

AU - Hearnshaw, J. B.

AU - Itow, Y.

AU - Korpela, A. V.

AU - Ling, C. H.

AU - Masuda, K.

AU - Matsubara, Y.

AU - Miyake, N.

AU - Muraki, Y.

AU - Ohnishi, K.

AU - Rattenbury, N. J.

AU - Saito, To

AU - Sullivan, D.

AU - Sumi, T.

AU - Suzuki, D.

AU - Sweatman, W. L.

AU - Tristram, P. J.

AU - Wada, K.

AU - Allan, A.

AU - Bode, M. F.

AU - Bramich, D. M.

AU - Clay, N.

AU - Fraser, S. N.

AU - Hawkins, E.

AU - Kerins, E.

AU - Lister, T. A.

AU - Mottram, C. J.

AU - Saunders, E. S.

AU - Snodgrass, C.

AU - Steele, I. A.

AU - Wheatley, P. J.

AU - Bozza, V.

AU - Browne, P.

AU - Burgdorf, M. J.

AU - Calchi Novati, S.

AU - Dreizler, S.

AU - Finet, F.

AU - Glitrup, M.

AU - Grundahl, F.

AU - Harpsøe, K.

AU - Hessman, F. V.

AU - Hinse, T. C.

AU - Hundertmark, M.

AU - Liebig, C.

AU - Maier, G.

AU - Mancini, L.

AU - Rahvar, S.

AU - Ricci, D.

AU - Scarpetta, G.

AU - Skottfelt, J.

AU - Southworth, J.

AU - Surdej, J.

AU - Zimmer, F.

N1 - Funding Information: We are very grateful to the observatories that support our science (Bronberg, Canopus, CTIO, ESO, IRSF, LCOGT, Liverpool, LOAO, MOA, OGLE, Perth, SAAO, Skinakas) via the generous allocation of time that makes this work possible. The operation of Canopus Observatory is in part supported by a financial contribution from David Warren. Allocation of the Holmes grant from the French Agence Nationale de la Recherche has been indispensable to finance observing trips and travel costs for meetings, and is gratefully acknowledged here. D.H. was supported by Czech Science Foundation grant GACR 205/07/0824 and by the Czech Ministry of Education project MSM0021620860. C.H. was supported by the grant 2009-0081561 of National Research Foundation of Korea. T.C.H. was financed for his astronomical research at the Armagh Observatory by the Department for Culture, Arts and Leisure, Northern Ireland, UK and is now supported by the Korea Research Council for Fundamental Science and Technology (KRCF) via the Young Scientist Research Fellowship Program. MOA project was funded by JSPS18253002 and JSPS20340052. T.S. was funded by JSPS20740104. D.R. and J.S. acknowledge support from the Communauté française de Belgique – Actions de recherche concertées – Académie universitaire Wallonie-Europe. P.F. wishes to thank Noriyuki Matsunaga for discussions about the interplay between adopted distance and derived extinction. The research leading to these results has received funding from the European Community’s Seventh Framework Programme (/FP7/2007-2013/) under grant agreement No 229517. A. Gould acknowledges support from NSF AST-1103471. B. S. Gaudi, A. Gould, and R. W. Pogge acknowledge support from NASA grant NNG04GL51G. Work by J. C. Yee is supported by a National Science Foundation Graduate Research Fellowship under Grant No. 2009068160. Work by S. Dong was performed under contract with the California Institute of Technology (Caltech) funded by NASA through the Sagan Fellowship Program. The RoboNet team is supported by the Qatar Foundation through QNRF grant NPRP-09-476-1-78. CUL acknowledges support by Korea Astronomy and Space Science Institute (KASI) grant 2012-1-410-02. This publication makes use of data products from the 2MASS project, as well as the SIMBAD database, Aladin and Vizier catalogue operation tools (CDS Strasbourg, France). The Two Micron All Sky Survey is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This work was granted access to the HPC resources of CALMIP under the allocation 2012-[1131].

PY - 2012

Y1 - 2012

N2 - Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted. Aims. MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration. Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit. Methods. Thanks to observations by all the collaborations, this event was well monitored. We first decided to characterize the source star properties by using a more refined method than the classical one: we measure the interstellar absorption along the line of sight in five different passbands (VIJHK). Secondly, we model the lightcurve by using the standard technique: make (s,q,α) grids to look for local minima and refine the results by using a downhill method (Markov chain Monte Carlo). Finally, we use a Galactic model to estimate the physical properties of the lens components. Results. We find that the source star is a giant G star with radius 9 R ·. The grid search gives two local minima, which correspond to the theoretical degeneracy s s-1. We find that the lens is composed of a brown dwarf secondary of mass MS = 0.05 M· orbiting a primary M-star of mass MP = 0.18 M·. We also reveal a new mass-ratio degeneracy for the central caustics of close binaries. Conclusions. As far as we are aware, this is the first detection using the microlensing technique of a binary system in our Galaxy composed of an M-star and a brown dwarf.

AB - Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted. Aims. MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration. Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit. Methods. Thanks to observations by all the collaborations, this event was well monitored. We first decided to characterize the source star properties by using a more refined method than the classical one: we measure the interstellar absorption along the line of sight in five different passbands (VIJHK). Secondly, we model the lightcurve by using the standard technique: make (s,q,α) grids to look for local minima and refine the results by using a downhill method (Markov chain Monte Carlo). Finally, we use a Galactic model to estimate the physical properties of the lens components. Results. We find that the source star is a giant G star with radius 9 R ·. The grid search gives two local minima, which correspond to the theoretical degeneracy s s-1. We find that the lens is composed of a brown dwarf secondary of mass MS = 0.05 M· orbiting a primary M-star of mass MP = 0.18 M·. We also reveal a new mass-ratio degeneracy for the central caustics of close binaries. Conclusions. As far as we are aware, this is the first detection using the microlensing technique of a binary system in our Galaxy composed of an M-star and a brown dwarf.

KW - Binaries: general

KW - Gravitational lensing: micro

KW - Stars: individual: MOA 2009-BLG-411L

UR - http://www.scopus.com/inward/record.url?scp=84867862201&partnerID=8YFLogxK

U2 - 10.1051/0004-6361/201219765

DO - 10.1051/0004-6361/201219765

M3 - مقالة

SN - 0004-6361

VL - 547

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A55

ER -

A brown dwarf orbiting an M-dwarf: MOA 2009-BLG-411L

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Keywords

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