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Probing the atmosphere of a solar-like star by galactic microlensing at high magnification

F. Abe·D. P. Bennett·I. A. Bond·J. J. Calitz·A. Claret·K. H. Cook·Y. Furuta·A. Gal-Yam·J-F. Glicenstein·J. B. Hearnshaw·P. H. Hauschildt·D. Kent·P. M. Kilmartin·Y. Kurata·K. Masuda·D. Maoz·Y. Matsubara·P. J. Meintjes·M. Moniez·Y. Muraki·S. Noda·E. O. Ofek·K. Okajima·L. Philpott·N. J. Rattenbury·S. H. Rhie·T. Sako·D. J. Sullivan·T. Sumi·D. M. Terndrup·P. J. Tristram·T. Yanagisawa·P. C. M. Yock
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Abstract

We report a measurement of limb darkening of a solar-like star in the very high magnification microlensing event MOA 2002-BLG-33. A 15 hour deviation from the light curve profile expected for a single lens was monitored intensively in V and I passbands by five telescopes spanning the globe. Our modelling of the light curve showed the lens to be a close binary system whose centre-of-mass passed almost directly in front of the source star. The source star was identified as an F8-G2 main sequence turn-off star. The measured stellar profiles agree with current stellar atmosphere theory to within ~4% in two passbands. The effective angular resolution of the measurements is <1 micro-arcsec. These are the first limb darkening measurements obtained by microlensing for a Solar-like star.

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F. Abe, D. P. Bennett, I. A. Bond, J. J. Calitz, A. Claret, K. H. Cook, Y. Furuta, A. Gal-Yam, J-F. Glicenstein, J. B. Hearnshaw, P. H. Hauschildt, D. Kent, P. M. Kilmartin, Y. Kurata, K. Masuda, D. Maoz, Y. Matsubara, P. J. Meintjes, M. Moniez, Y. Muraki, S. Noda, E. O. Ofek, K. Okajima, L. Philpott, N. J. Rattenbury, S. H. Rhie, T. Sako, D. J. Sullivan, T. Sumi, D. M. Terndrup, P. J. Tristram, T. Yanagisawa, P. C. M. Yock. 2003-10-15. Probing the atmosphere of a solar-like star by galactic microlensing at high magnification. https://doi.org/10.1051/0004-6361%3A20031602

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