硅星HR 7224的光变性质
The nature of the light variability of the silicon star HR 7224
摘要：
虽然化学奇特（CP）星的光度变化经常被用来确定它们的自转周期，但它们的光变的详细机制仍然知之甚少。我们使用观测到的硅和铁的表面分布模拟恒星HR 7224的光变。我们使用的TLUSTY模型计算适当的硅和铁丰度的大气，以获得出射通量和预测旋转调制的光变曲线的恒星。我们还获得了额外的光度测量，并采用我们自己的回归程序，以获得更精确的估计轻元素。我们表明，恒星的光变化可以解释为一个结果：i）不均匀的表面分布的元素，ii）从紫外线到可见光部分的光谱的流量重新分配，和iii）旋转的恒星。我们发现，硅束缚-自由过渡和铁束缚-束缚过渡提供的主要贡献的通量重新分配，虽然需要一个额外的来源的不透明度。我们确认，许多铁线显着有助于众所周知的抑郁症在5200 A，并讨论铁丰度和值的特殊性指数a之间的联系。硅和铁的不均匀表面分布能够解释恒星HR 7224中大部分的旋转调制光变化。
英文摘要：
Although photometric variations of chemically peculiar (CP) stars are frequently used to determine their rotational periods, the detailed mechanism of their light variability remains poorly understood. We simulate the light variability of the star HR 7224 using the observed surface distribution of silicon and iron. We used the TLUSTY model atmospheres calculated for the appropriate silicon and iron abundances to obtain the emergent flux and to predict the rotationally modulated light curve of the star. We also obtained additional photometric measurements and employed our own regression procedure to derive a more precise estimate of the light elements. We show that the light variation of the star can be explained as a result of i) the uneven surface distribution of the elements, ii) the flux redistribution from the ultraviolet to the visible part of the spectrum, and iii) rotation of the star. We show that the silicon bound-free transitions and iron bound-bound transitions provide the main contribution to the flux redistribution, although an additional source of opacity is needed. We confirm that numerous iron lines significantly contribute to the well-known depression at 5200 A and discuss the connection between iron abundance and the value of peculiarity index a. The uneven surface distribution of silicon and iron is able to explain most of the rotationally modulated light variation in the star HR 7224.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
