SPECTRAL LINE-DEPTH RATIOS AS TEMPERATURE INDICATORS FOR COOL STARS
SPECTRAL LINE-DEPTH RATIOS AS TEMPERATURE INDICATORS FOR COOL STARS
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光谱线深度比作为冷恒星的温度指标
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
D. F. Gray
中科院分区：
文献类型：
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作者：
D. F. Gray
光谱线深比作为G矮星和K矮星的恒星温度计的使用，比早期的研究（Gray和约翰逊，1991年）更加完善。与1991年工作中使用的lambda-6252 V I与lambda-6253 Fe I比值一样，包含任何饱和度的线的比值产生金属丰度相关的结果。这种依赖性在这里进行调查，并得出一个修正。10线深度比仅使用弱线被证明具有可忽略不计的metallicty的依赖性和解决的温度差异小至6 K的早期K矮星从一个单一的曝光具有信噪比为500。对于这些特定的谱线，精度向G 0严重恶化。较小的温差可以通过组合曝光来解决。给出了65颗矮星的相对温度，其中一些的误差接近1 K.从颜色指数和光谱线导出的温度之间的约50 K的增量最有可能是星际变红影响测光的结果。
The use of spectral line-depth ratios as a stellar thermometer in G and K dwarfs is developed and refined beyond an earlier study (Gray and Johnson 1991). Ratios incorporating a line with any degree of saturation, as with the lambda-6252 V I to lambda-6253 Fe I ratio used in the 1991 work, produce metallicity dependent results. This dependence is investigated here, and a correction derived. Ten line-depth ratios using only weak lines are shown to have negligible metallicty dependence and resolve temperature differences as small as 6 K for early K dwarfs from a single exposure having a signal-to-noise ratio of 500. Precision deteriorates badly toward G0 for these particular spectral lines. Smaller temperature differences can be resolved by combining exposures. Relative temperatures of 65 dwarfs are given, a few having errors near 1 K. Inconsistencies ~50 K between temperatures derived from color indices and from spectral lines are most likely a result of interstellar reddening affecting the photometry.