DETERMINATION OF STELLAR RADII FROM ASTEROSEISMIC DATA
DETERMINATION OF STELLAR RADII FROM ASTEROSEISMIC DATA
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DOI：
10.1088/0004-637x/710/2/1596
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发表时间：
2009-09
期刊：
影响因子：
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通讯作者：
S. Basu;W. Chaplin;Y. Elsworth
中科院分区：
文献类型：
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作者：
S. Basu;W. Chaplin;Y. Elsworth
美国宇航局开普勒使命的目的是通过凌日发现行星。被探测行星的准确和精确半径取决于准确地知道宿主星星的半径，这是困难的，除非精确地知道星星的温度和光度。然而，开普勒有一个星震学计划，可以提供地震变量，可以轻松，准确和非常精确地描述恒星半径。本文介绍了Yale-Birmingham（YB）方法，利用地震变量和常规变量的组合确定恒星半径，并分析了这些变量对结果的影响。我们发现，对于主序星，视差的知识是不重要的，以获得准确的半径使用YB方法：我们可以得到结果的准确性和精度优于百分之几，如果我们知道这些恒星的有效温度和地震参数。金属性也没有多大区别。然而，对有效温度和金属丰度沿着地震参数的良好估计对于正确确定次巨星的半径至关重要。另一方面，对于红巨星，我们发现，如果没有对视差的良好估计，就不可能正确地确定半径。我们发现，在地震数据中的所谓的“表面项”的推断半径的影响很小。在某些情况下，对流混合长度的不确定性可能很重要，并可能导致推断半径的系统性变化。盲测试模拟数据，以匹配那些预期从开普勒的asteroseismic调查阶段表明，它将有可能成功地推断恒星半径使用我们的方法。
The NASA Kepler mission is designed to find planets through transits. Accurate and precise radii of the detected planets depend on knowing the radius of the host star accurately, which is difficult unless the temperature and luminosity of the star are known precisely. Kepler, however, has an asteroseismology program that will provide seismic variables that can characterize stellar radii easily, accurately, and extremely precisely. In this paper, we describe the Yale–Birmingham (YB) method to determine stellar radii using a combination of seismic and conventional variables and analyze the effect of these variables on the result. We find that for main-sequence stars, a knowledge of the parallax is not important to get accurate radii using the YB method: we can get results to an accuracy and precision of better than a few percent if we know the effective temperature and the seismic parameters for these stars. Metallicity does not make much difference either. However, good estimates of the effective temperature and metallicity, along with those of the seismic parameters, are essential to determine radii of subgiants properly. On the other hand, for red giants we find that determining radii properly is not possible without a good estimate of the parallax. We find that the so-called “surface term” in the seismic data has minimal effect on the inferred radii. Uncertainties in the convective mixing length can matter under some circumstances and can cause a systematic shift in the inferred radii. Blind tests with data simulated to match those expected from the asteroseismic survey phase of Kepler show that it will be possible to infer stellar radii successfully using our method.