Many early-type stars have oblate surfaces, spatial temperature variations, and spectral line broadening that indicate large rotational velocities. Rotation ought to have a significant effect on the full spectra of such stars. To infer structural and life history parameters from their spectra, one must integrate specific intensity over the two-dimensional surfaces of corresponding stellar models. Toward this end, we offer PARS (Paint the Atmospheres of Rotating Stars) -- an integration scheme based on models that incorporate solid body rotation, Roche mass distribution, and collinearity of gravity and energy flux (this https URL). The scheme features a closed-form expression for the azimuthal integral, a high-order numerical approximation of the longitudinal integral, and a precise calculation of surface effective temperature at rotation rates up to 99.9% of Keplerian limit. Extensions of the scheme include synthetic color-magnitude diagrams and planetary transit curves.

中文翻译：

---

旋转星的合成光谱

许多早型恒星具有扁圆的表面、空间温度变化和谱线加宽，表明自转速度很大。自转应该对这些恒星的全光谱产生重大影响。为了从光谱推断结构和生命史参数，必须在相应恒星模型的二维表面上整合特定强度。为此，我们提供了 PARS（绘制旋转星的大气层）——一种基于模型的集成方案，该模型包含固体旋转、罗氏质量分布以及重力和能量通量的共线性（此 https URL）。该方案具有方位积分的封闭形式表达式，纵向积分的高阶数值近似，以及在高达开普勒极限 99.9% 的旋转速率下精确计算表面有效温度。该方案的扩展包括合成色等图和行星凌日曲线。