标题： 远紫外连续谱发射：将此诊断方法应用于太阳质量恒星的色球层 显示英文标题

标题： Far Ultraviolet Continuum Emission: Applying this Diagnostic to the Chromospheres of Solar-Mass Stars

摘要： 远紫外（FUV）连续谱通量被认为是太阳低色球层温度结构的一个非常敏感的诊断工具。到目前为止，对现有恒星FUV数据的分析表明，类太阳恒星也必须有色球层，但对恒星FUV连续谱的定量分析需要质量更高的光谱以及与新的非局部热平衡色球模型进行比较。我们提供了精确的远紫外（FUV，1150-1500^{\circ }）连续谱通量测量结果，这得益于哈勃空间望远镜上的宇宙起源光谱仪（COS）的高通光率和极低的探测器背景。我们表明，即使对于我们样本中最暗的恒星，也可以在探测器背景之上测量连续谱通量。我们发现，在所有FUV波长下，随着旋转周期的减少，连续谱亮度温度明显增加，这为恒星色球层中的磁加热率提供了一个重要的测量方法。与半经验太阳通量模型比较显示，旋转最快的类太阳质量恒星的FUV连续谱亮度温度类似于太阳上最亮的亮斑。因此，最亮的太阳亮斑的热结构为我们的样本中旋转最快的类太阳质量恒星的热结构和加热率提供了一个初步估计。 显示英文摘要

摘要： The far ultraviolet (FUV) continuum flux is recognized as a very sensitive diag- nostic of the temperature structure of the Sun's lower chromosphere. Until now analysis of the available stellar FUV data has shown that solar-type stars must also have chromospheres, but quantitative analyses of stellar FUV continua require far higher quality spectra and comparison with new non-LTE chromosphere models. We present accurate far ultraviolet (FUV, 1150-1500^{\circ}) continuum flux measurements for solar-mass stars, made feasible by the high throughput and very low detector background of the Cosmic Origins Spectrograph (COS) on the Hubbble Space Telescope. We show that the continuum flux can be measured above the detector background even for the faintest star in our sample. We find a clear trend of increasing continuum brightness temperature at all FUV wavelengths with decreasing rotational period, which provides an important measure of magnetic heating rates in stellar chromospheres. Comparison with semiempirical solar flux models shows that the most rapidly rotating solar-mass stars have FUV continuum brightness temperatures similar to the brightest faculae seen on the Sun. The thermal structure of the brightest solar faculae therefore provides a first-order estimate of the thermal structure and heating rate for the most rapidly rotating solar-mass stars in our sample.