Institute of Theoretical Physics · Faculty of Mathematics and Physics, Charles University
In: Kerins, E.; Mao, S.; Rattenbury, N.; Wyrzykowski, L. (eds.) Proceedings of the Manchester Microlensing Conference: The 12th International Conference and ANGLES Microlensing Workshop. Proceedings of Science, pp. 028 (2008)
A number of caustic-crossing microlensing events have been used to measure limb-darkening coefficients of their source stars. We point out that the usage of analytical limb-darkening laws generally involves two potential problems. First, the tabulated stellar model-atmosphere limb-darkening
coefficients are usually computed by a method strongly biased to fitting the stellar limb. Second, even when using less biased coefficients for comparison, the linear law tends to have problems with overall fit quality as well as with flux conservation, and higher-order coefficients can rarely be satisfactorily constrained fromlight-curve analysis. An alternative approach is to use a "best possible" limb-darkening model directly obtained by principal component analysis (PCA) of model atmospheres. We use a model constructed from Kurucz’s full ATLAS9 atmosphere grid, and demonstrate its superior quality in describing limb-darkening profiles. As an example, we analyze the point-lens event OGLE 2004–BLG–254 using the linear law and the PCA limb-darkening model.
@inproceedings{UTF730,
author = {Heyrovský, D.},
title = {{How to treat stellar limb darkening in the analysis of microlensing events}},
booktitle = {Kerins, E.; Mao, S.; Rattenbury, N.; Wyrzykowski, L. (eds.) Proceedings of the Manchester Microlensing Conference: The 12th International Conference and ANGLES Microlensing Workshop. Proceedings of Science},
volume = {GMC8},
pages = {028},
year = {2008},
doi = {10.22323/1.054.0028},
url = {https://pos.sissa.it/054/028/pdf},
}