研究了红巨星冷温区的辐射热改正（BC）的变化趋势及其与恒星金属丰度的关系。我们的分析依赖于在3500 A-2.5微米波长范围内对5个（3个球状+2个疏散）银河系星团中92颗红巨星的广泛的光学-红外光谱观测样本，沿着-2.2<[Fe/H]<+0.4金属丰度范围。测辐射热星等的内部精度只有百分之几。利用我们的新数据库，我们提供了一套拟合函数的V和K BC与Teff和宽带颜色，有效的区间3300 K <Teff<5000 K，特别适合于红巨人。没有发现BC（V）和BC（K）随[Fe/H]的明显漂移。然而，对于B带校正，情况可能有所不同，因为我们的数据具有明确的（B-V）与[Fe/H]的相关性，对于固定的Teff，贫金属恒星相对于富金属样本显示“更蓝”（B-V）。我们的经验辐射热标度支持这样的结论：（a）最近研究的BC（K）在本文所考虑的整个色/温范围内在<0.1 mag内是可靠的，（b）同样的结论仅适用于温度高于~ 3800 K的恒星的BC（V）。在较冷的温度下，协议是不太普遍的，MARCS模式是唯一提供一个令人满意的匹配观测。
英文摘要：
We have investigated the relevant trend of the bolometric correction (BC) at the cool-temperature regime of red giant stars and its possible dependence on stellar metallicity. Our analysis relies on a wide sample of optical-infrared spectroscopic observations, along the 3500A-2.5micron wavelength range, for a grid of 92 red giant stars in five (3 globular + 2 open) Galactic clusters, along the -2.2<[Fe/H]<+0.4 metallicity range. Bolometric magnitudes have been found within an internal accuracy of a few percent. Making use of our new database, we provide a set of fitting functions for the V and K BC vs. Teff and broad-band colors, valid over the interval 3300K<Teff<5000K, especially suited for Red Giants. No evident drift of both BC(V) and BC(K) with [Fe/H] is found. Things may be different, however, for the B-band correction, given a clear (B-V) vs. [Fe/H] correlation in place for our data, with metal-poor stars displaying a "bluer" (B-V) with respect to the metal-rich sample, for fixed Teff. Our empirical bolometric scale supports the conclusion that (a) BC(K) from the most recent studies are reliable within <0.1 mag over the whole color/temperature range considered in this paper, and (b) the same conclusion apply to BC(V) only for stars warmer than ~3800K. At cooler temperatures the agreement is less general, and MARCS models are the only ones providing a satisfactory match to observations.
Synthetic Stellar Photometry - II. Testing the bolometric flux scale, and tables of bolometric corrections for the Hipparcos/Tycho, Pan-STARRS1, SkyMapper and JWST systems
我们使用MARCS模式的大气通量计算合成颜色，测辐射热校正和红化系数的依巴谷/第谷，泛STARRS 1，SkyMapper和JWST系统。提供了表格和插值子程序，用于将等时线从理论平面转换到各种观测平面，推导出2600 K < Teff < 8000 K时HR图上几乎任何给定点处的测热校正、合成色和色温关系，以及85个光度滤波器中的不同红化值。我们使用绝对分光光度法从CALSPEC库显示，热辐射通量可以恢复到2%的热辐射校正在一个单一的波段，当输入恒星参数是众所周知的FG矮星在各种金属丰度。这一唯一的不确定性来源对干涉测量有效温度的影响约为0.5%（或在太阳温度下为30 K）。当结合更多波段的测热校正时，不确定性减半，并受到当前绝对通量尺度1%的基本不确定性的限制。RAVE DR 5星表中的恒星用于验证我们的MARCS合成测光在光学和红外范围内的选定滤光片中的质量。这项调查表明，现存的MARCS合成通量能够再现银河系盘上恒星星族中观察到的主要特征。
Stellar lifetime and ultraviolet properties of the old metal-rich Galactic open cluster NGC6791: a pathway to understand the UV upturn of elliptical galaxies
