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

• Published in: Astronomy and astrophysics (Berlin) Vol. 411; no. 3; pp. L493 - L496
• Main Authors: Abe, F., Bennett, D. P., Bond, I. A., Calitz, J. J., Claret, A., Cook, K. H., Furuta, Y., Gal-Yam, A., Glicenstein, J.-F., Hearnshaw, J. B., Hauschildt, P. H., Kent, D., Kilmartin, P. M., Kurata, Y., Masuda, K., Maoz, D., Matsubara, Y., Meintjes, P. J., Moniez, M., Muraki, Y., Noda, S., Ofek, E. O., Okajima, K., Philpott, L., Rattenbury, N. J., Rhie, S. H., Sako, T., Sullivan, D. J., Sumi, T., Terndrup, D. M., Tristram, P. J., Yanagisawa, T., Yock, P. C. M.
• Format: Journal Article
• Language: English
• Published: EDP Sciences 01.12.2003
• Subjects: stars: individual: MOA 2002–BLG–33; stars: limb darkening; techniques: gravitational microlensing; techniques: high angular resolution
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:20031602

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 μas. These are the first limb darkening measurements obtained by microlensing for a Solar-like star.