标题： 热恒星种群合成从紫外光谱：球状星团 M79 (NGC 1904) 显示英文标题

标题： Hot stellar population synthesis from the UV spectrum: the globular cluster M79 (NGC 1904)

摘要： 我们分析了球状星团M79的远紫外光谱。 我们表明，根据Dixon等人（1996年）得出的零年龄水平分支恒星的近高斯质量分布，如果在HUT入口狭缝内有一颗有效温度约为9500 K的明亮紫外亮星，或者更可能的是，如果水平分支形态在M79核心变得明显更红，如在其他中心致密的球状星团中观察到的那样，那么该分布能够再现远紫外霍普金斯紫外望远镜（HUT）光谱。 如果热水平分支恒星中重元素的表面丰度因辐射扩散而增强，M79的合成光谱和观测光谱之间的吻合度也将得到改善。 与Dixon等人（1996年）相反，我们不需要极低的重力来再现Ly alpha的宽度。 显示英文摘要

摘要： We have analyzed the far UV-spectrum of the globular cluster M79. We show that the nearly Gaussian mass distribution of zero-age horizontal-branch stars, as derived by Dixon et al.(1996), is able to reproduce the far-UV Hopkins Utraviolet Telescope (HUT) spectrum, if there is a luminous UV-bright star of about an effective temperature of 9,500 K within the HUT entrance slit, or, more likely, if the horizontal branch morphology becomes considerably redder in the core of M79, as observed in some other centrally condensed globular clusters. Agreement between the synthetic and observed far-UV spectra for M79 would also be improved if the surface abundances of the heavy elements in the hot horizontal-branch stars were enhanced by radiative diffusion. Contrary to Dixon et al. (1996) we do not need extremely low gravities to reproduce the width of Ly alpha.