论文标题
紧凑型恒星的重力和肢体变形系数:da,db和dba黯然失色的白色矮人
Gravity and limb-darkening coefficients for compact stars: DA, DB, and DBA eclipsing white dwarfs
论文作者
论文摘要
本工作的主要目的是通过计算具有氢,氦气或混合组成(DA,DB和DBA类型)的白矮人大气模型的重力和肢体变形系数。 我们计算了DA,DB和DBA白色矮人大气模型的重力和肢体变形系数,涵盖了Sloan,Ubvri,Kepler,Tess,Tess和Gaia光度法系统的传输曲线。还进行了hipercam仪器的特定计算。对于肢体变形系数的所有计算,我们使用了最小二乘方法。关于潮汐和旋转扭曲的影响,我们还首次使用与肢体变化的恒星大气模型使用相同的恒星大气模型来计算重力 - 划线系数$ y(λ)$(λ)$。引入了更一般的微分方程来得出这些数量,包括部分衍生$ \ left(\ partial {\ ln i_o(λ)}/{\ partial {\ partial {\ ln g}} \ right)_ {t _ {t _ {t _ {\ rm eff}} $。 采用了六个定律来描述特定强度分布:线性,二次,平方根,对数,功率-2和一个具有四个系数的更通用的法律。为化学成分日志[H/HE] = $ - $ 10.0(db),$ -2.0(DBA)和He/H = 0(DA)提出了计算,log G在5.0到9.5之间变化在5.0到9.5之间,有效温度在3750 K-100 \,000 K之间,有效温度在000 k中均高于40 \ 000 k的有效温度。采用的混合长度参数为ML2/$α= 0.8 $(DA情况)和1.25(DB和DBA)。结果以112表的形式呈现。可以根据要求执行其他计算,例如其他光度法系统和/或LOG [H/HE],$ \ log G,$和T $ _ {\ rm eff} $的不同值。
The main objective of the present work is to extend these investigations by computing the gravity and limb-darkening coefficients for white dwarf atmosphere models with hydrogen, helium, or mixed compositions (types DA, DB, and DBA). We computed gravity and limb-darkening coefficients for DA, DB, and DBA white dwarfs atmosphere models, covering the transmission curves of the Sloan, UBVRI, Kepler, TESS, and Gaia photometric systems. Specific calculations for the HiPERCAM instrument were also carried out. For all calculations of the limb-darkening coefficients we used the least-squares method. Concerning the effects of tidal and rotational distortions, we also computed for the first time the gravity-darkening coefficients $y(λ)$ for white dwarfs using the same models of stellar atmospheres as in the case of limb-darkening. A more general differential equation was introduced to derive these quantities, including the partial derivative $\left(\partial{\ln I_o(λ)}/{\partial{\ln g}}\right)_{T_{\rm eff}}$. Six laws were adopted to describe the specific intensity distribution: linear, quadratic, square root, logarithmic, power-2, and a more general one with four coefficients. The computations are presented for the chemical compositions log[H/He] = $-$10.0 (DB), $-$2.0 (DBA) and He/H = 0 (DA), with log g varying between 5.0 and 9.5 and effective temperatures between 3750 K-100\,000 K. For effective temperatures higher than 40\,000 K, the models were also computed adopting nonlocal thermal equilibirum (DA). The adopted mixing-length parameters are ML2/$α= 0.8$ (DA case) and 1.25 (DB and DBA). The results are presented in the form of 112 tables. Additional calculations, such as for other photometric systems and/or different values of log[H/He], $\log g,$ and T$_{\rm eff}$ can be performed upon request.