A comparison of DA white dwarf temperatures and gravities from Lyman and Balmer line studies
A comparison of DA white dwarf temperatures and gravities from Lyman and Balmer line studies
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莱曼线和巴尔默线研究中 DA 白矮星温度和重力的比较
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
F. Meru
中科院分区：
文献类型：
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作者：
M. Barstow;J. Holberg;I. Hubeny;S. Good;A. Levan;F. Meru
利用HUT、ORFES和FUSE远紫外空间发射的莱曼线数据，我们测量了一个热DA白色矮星样品的有效温度和表面重力。与标准Balmer线技术的结果比较，我们发现两种方法之间有一个普遍良好的总体一致性。然而，对于一些恒星，我们发现了显著的差异，但并不总是具有一致的性质，因为有时巴耳末温度超过了从莱曼线得出的温度，而在其他情况下则更低。我们的结论是，用最新的模式大气计算，这些差异可能不是由于对莱曼线的理论处理不充分，而是由于观测和数据处理过程中的系统性影响，这些影响在这些谱中占主导地位。如果这些系统的数据减少的影响可以得到充分的控制，莱曼线的温度和重力测量是一致的，当津贴合理的观测不确定性时，从Balmer线获得的。关键词：恒星：大气-恒星：白色矮星-紫外：恒星。
ABSTRACT We present measurements of the effective temperatures and surface gravities fora sample of hot DA white dwarfs, using the Lyman line data available from the HUT,ORFEUSand FUSEfar-UV spacemissions. Comparingthe results with those from thestandard Balmer line technique, we find that there is a general good overall agreementbetween the two methods. However, significant differences are found for a number ofstars, but not always of a consistent nature in that sometimes the Balmer temperatureexceeds that derived from the Lyman lines and in other instances is lower. We concludethat, with the latest model atmosphere calculations, these discrepancies probably donot arise from an inadequate theoretical treatment of the Lyman lines but rather fromsystematic effects in the observation and data reduction processes, which dominatethe statistical errors in these spectra. If these systematic data reduction effects canbe adequately controlled, the Lyman line temperature and gravity measurements areconsistent with those obtained from the Balmer lines when allowance is made forreasonable observational uncertainties.Key words: stars:atmospheres – stars:white dwarfs – ultraviolet:stars.