Limb-darkening measurements for a cool red giant in microlensing event OGLE 2004-BLG-482
Limb-darkening measurements for a cool red giant in microlensing event OGLE 2004-BLG-482
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微透镜事件 OGLE 2004-BLG-482 中冷红巨星的肢体变暗测量
DOI：
10.1051/0004-6361/200912007
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发表时间：
2009
影响因子：
6.5
通讯作者：
L. Wyrzykowski
中科院分区：
文献类型：
--
作者：
M. Zub;A. Cassan;D. Heyrovský;P. Fouqué;H. C. Stempels;M. Albrow;J. Beaulieu;S. Brillant;G. Christie;N. Kains;S. Kozłowski;D. Kubas;J. Wambsganss;V. Batista;D. Bennett;K. Cook;C. Coutures;S. Dieters;M. Dominik;D. Prester;J. Donatowicz;J. Greenhill;K. Horne;U. Jørgensen;S. Kane;J. Marquette;R. Martin;J. Menzies;K. Pollard;K. Sahu;C. Vinter;A. Williams;A. Gould;D. Depoy;A. Gal;B. Gaudi;C. Han;Y. Lipkin;D. Maoz;E. Ofek;B.;R. Pogge;J. Mccormick;A. Udalski;M. Szymański;M. Kubiak;G. Pietrzyński;I. Soszyński;O. Szewczyk;L. Wyrzykowski
目标。我们详细分析了OGLE 2004-BLG-482，这是一个相对较高倍率的单透镜微透镜事件，表现出明显的扩展源效应。这些事件相对罕见，但它们可能包含关于其来源恒星的恒星大气属性的独特信息，如这项研究所示。方法：研究方法。我们对整个光线曲线的密集光度测量覆盖和适当的微透镜模型使我们能够在三个波段(包括标准的强森-考辛斯I和R、S以及宽清晰滤光片)中对Ogle2004-BLG-482源恒星的线性边缘暗化系数进行测量。特别是，我们详细地讨论了多波段和多站点建模的问题，以达到我们的结果的预期精度。我们还获得了高分辨率的UVES光谱，作为ESO VLT TOO程序的一部分，我们从这些光谱中得出了源星的精确基本参数。结果。从高分辨率的UVES光谱可以看出，OGLE2004-BLG-482‘S源星是一颗稍晚于M3的MK型红巨星，其TJeff=3667±150K，logg=2.1±1.0，假定太阳金属丰度。OGLE校准的彩色−震级图证实了这一点。然后，我们从详细的微透镜模型中获得了光曲线的线性边缘变暗系数，并将其与文献中提供的模型大气预测进行了比较，发现I和R波段的预测结果非常一致。此外，基于ATLAS肢体变暗轮廓的主成分分析，我们使用肢体变暗的另一种描述进行了类似的分析，并且在测量和模型预测之间也发现了非常好的一致性。
Aims. We present a detailed analysis of OGLE 2004-BLG-482, a relatively high-magnification single-lens microlensing event that exhibits clear extended-source effects. These events are relatively rare, but they potentially contain unique information on the stellar atmosphere properties of their source star, as shown in this study. Methods. Our dense photometric coverage of the overall light curve and a proper microlensing modelling allow us to derive measurements of the OGLE 2004-BLG-482source star’s linear limb-darkening coefficients in three bands, including standard Johnson-Cousins I and R ,a s well as in a broad clear filter. In particular, we discuss in detail the problems of multi-band and multi-site modelling on the expected precision of our results. We also obtained high-resolution UVES spectra as part of a ToO programme at ESO VLT, from which we derive the source star’s precise fundamental parameters. Results. From the high-resolution UVES spectra, we find that OGLE 2004-BLG-482’s source star is a red giant of MK type a bit later than M3, with Teff = 3667 ± 150 K, log g = 2.1 ± 1.0 and an assumed solar metallicity. This is confirmed by an OGLE calibrated colour−magnitude diagram. We then obtain from a detailed microlensing modelling of the light curve linear limb-darkening coefficients that we compare to model-atmosphere predictions available in the literature, and find a very good agreement for the I and R bands. In addition, we perform a similar analysis using an alternative description of limb darkening based on a principal component analysis of ATLAS limb-darkening profiles, and also find a very good agreement between measurements and model predictions.
DOI：
10.1111/j.1365-2966.2009.15098.x
发表时间：
2009-05
影响因子：
4.8
作者：
M. Albrow;K. Horne;D. Bramich;P. Fouqué;V. R. Miller;J. Beaulieu;C. Coutures;C. Coutures;J. Menzies;A. Williams;V. Batista;D. Bennett;S. Brillant;A. Cassan;S. Dieters;D. Prester;J. Donatowicz;J. Greenhill;N. Kains;S. Kane;D. Kubas;J. Marquette;K. Pollard;K. Sahu;Y. Tsapras;Y. Tsapras;J. Wambsganss;M. Zub
通讯作者：
M. Albrow;K. Horne;D. Bramich;P. Fouqué;V. R. Miller;J. Beaulieu;C. Coutures;C. Coutures;J. Menzies;A. Williams;V. Batista;D. Bennett;S. Brillant;A. Cassan;S. Dieters;D. Prester;J. Donatowicz;J. Greenhill;N. Kains;S. Kane;D. Kubas;J. Marquette;K. Pollard;K. Sahu;Y. Tsapras;Y. Tsapras;J. Wambsganss;M. Zub