摘要
介绍一种新的一级近似和二级近似描述恒星大气临边昏暗现象方法 ,其临边昏暗系数可通过有关物理量的直接测量或测量流量和辅助量恒星表面温度的方法间接给出 .经过与太阳观测比较和数值模型大气方法比较 ,均显示新方法能够以很精确的方式描述恒星临边昏暗关系 ,或确定其相应系数 .新方法对太阳观测的 1 76个数据比较了统计方差 ,其中直接法的一级近似和二级近似分别为 0 .38%和 0 .2 6% ;间接法的方差与此相近而略大 ;与数值模型大气比较其偏差范围从不足 1 %到一般小于 3% .
In this paper, some new methods, including the first order direct/indirect methods and the second order direct/indirect methods of describing the stellar limb darkening phenomena, are introduced. By using the methods, some measurable physical quantities are defined to constitute the coefficients of stellar limb darkening laws as direct or semi direct descriptions. The new methods are based on measurements and can be confirmed theoretically. They are simpler and more accurate than numerical method. They are also checked with Mihalas' model and shown to be better. By comparison with 176 observations of the sun, the mean differences of the direct results are only about 0.38% of the first order approaches and only about 0.26% of the second order approaches. The mean differences of the indirect results are slightly larger than the former. By comparison with the Non LTE numerical model results, there are differences usually only less than 1% and no more than 3%.
出处
《天文学报》
CSCD
北大核心
2000年第2期192-203,共12页
Acta Astronomica Sinica
基金
国家攀登计划资助!(项目号 :95 预 0 9)
关键词
恒星大气
临边昏暗系数
恒星
测定
stellar atmosphere, limb darkening approach, limb darkening coefficient
