Journal
ASTRONOMY & ASTROPHYSICS
Volume 518, Issue -, Pages -Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201014053
Keywords
gravitational lensing: micro; techniques: high angular resolution; stars: atmospheres; stars: individual: OGLE 2008-BLG-290
Categories
Funding
- Bronberg
- Canopus
- CTIO
- ESO
- IRSF
- LCOGT
- Liverpool
- LOAO
- MOA
- OGLE
- Perth
- SAAO
- Skinakas
- Polish MNiSW [N20303032/4275]
- French Agence Nationale de la Recherche
- Czech Science Foundation [GACR 205/07/0824]
- Czech Ministry of Education [MSM0021620860]
- National Research Foundation of Korea [2009-0081561]
- Department for Culture, Arts and Leisure, Northern Ireland, UK
- Communaute francaise de Belgique - Actions de recherche concertees - Academie universitaire Wallonie-Europe
- Danish National Research Council
- National Aeronautics and Space Administration
- National Science Foundation
- STFC [PP/E001149/1, ST/G002355/1, ST/G001987/1, PP/E002137/1, PP/D000955/1, PP/F000057/1, ST/H002391/1, ST/G009465/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/H002391/1, ST/G001987/1, PP/F000057/1, ST/G009465/1, PP/E001149/1, PP/E002137/1, ST/G002355/1, PP/D000955/1] Funding Source: researchfish
Ask authors/readers for more resources
Context. Not only is gravitational microlensing a successful tool for discovering distant exoplanets, but it also enables characterization of the lens and source stars involved in the lensing event. Aims. In high-magnification events, the lens caustic may cross over the source disk, which allows determination of the angular size of the source and measurement of its limb darkening. Methods. When such extended-source effects appear close to maximum magnification, the resulting light curve differs from the characteristic Paczy ' nski point-source curve. The exact shape of the light curve close to the peak depends on the limb darkening of the source. Dense photometric coverage permits measurement of the respective limb-darkening coefficients. Results. In the case of the microlensing event OGLE 2008-BLG-290, the K giant source star reached a peak magnification at about 100. Thirteen different telescopes have covered this event in eight different photometric bands. Subsequent light-curve analysis yielded measurements of linear limb-darkening coefficients of the source in six photometric bands. The best-measured coefficients lead to an estimate of the source effective temperature of about 4700(-200)(+100) K. However, the photometric estimate from colour-magnitude diagrams favours a cooler temperature of 4200 +/- 100 K. Conclusions. Because the limb-darkening measurements, at least in the CTIO/SMARTS2 V-s- and I-s-bands, are among the most accurate obtained, the above disagreement needs to be understood. A solution is proposed, which may apply to previous events where such a discrepancy also appeared.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available