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PLANET observations of microlensing event OGLE-1999-BUL-23: limb-darkening measurement of the source star
Citation
Albrow, MD and An, J and Beaulieu, J-P and Caldwell, JAR and DePoy, DL and Dominik, M and Gaudi, BS and Gould, A and Greenhill, JG and Hill, KM and Kane, S and Martin, R and Menzies, J and Pogge, RW and Pollard, KR and Sackett, PD and Sahu, KC and Vermaak, P and Watson, RD and Williams, A, PLANET observations of microlensing event OGLE-1999-BUL-23: limb-darkening measurement of the source star, The Astrophysical Journal, 549, (2) pp. 759-769. ISSN 0004-637X (2001) [Refereed Article]
DOI: doi:10.1086/319437
Abstract
We present PLANET observations of OGLE-1999-BUL-23, a binary-lens microlensing event toward the Galactic bulge. PLANET observations in the I and V bands cover the event from just before the first caustic crossing until the end of the event. In particular, a densely sampled second caustic crossing enables us to derive the linear limb-darkening coefficients of the source star: c v = 0.786 +0.080 -0.078 and c I = 0.632 +0.047 -0.037. Combined analysis of the light curve and the color-magnitude diagram suggests that the source star is a G/K subgiant in the Galactic bulge (T eff ≃ 4800 K). The resulting linear limb-darkening coefficient of the source is consistent with theoretical predictions, although it is likely that nonlinearity of the stellar surface brightness profile complicates the interpretation, especially for the I band. The global light curve fit to the data indicates that the event is due to a binary lens of a mass ratio q ≃ 0.39 and a projected separation d ≃ 2.42. The lens/source relative proper motion is (22.8 ± 1.5) km s -1 kpc -1, typical of bulge/bulge or bulge/disk events.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Research Division: | Physical Sciences |
| Research Group: | Astronomical sciences |
| Research Field: | Galactic astronomy |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding knowledge |
| Objective Field: | Expanding knowledge in the physical sciences |
| UTAS Author: | Beaulieu, J-P (Dr Jean-Philippe Beaulieu) |
| UTAS Author: | Greenhill, JG (Dr John Greenhill) |
| UTAS Author: | Hill, KM (Dr Kym Hill) |
| UTAS Author: | Kane, S (Dr Stephen Kane) |
| UTAS Author: | Watson, RD (Dr Bob Watson) |
| ID Code: | 22112 |
| Year Published: | 2001 |
| Web of Science® Times Cited: | 67 |
| Deposited By: | Physics |
| Deposited On: | 2001-08-01 |
| Last Modified: | 2022-06-03 |
| Downloads: | 0 |
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