Abstract—The importance of taking the SiO absorption in the infrared spectrum into account for spectral analysis of late-type stars is demonstrated. The lists of absorption lines of the fundamental SiO system calculated by the group of J. Tennison in the ExoMol project were used. The bands of isotopic molecules ²⁸SiO, ²⁹SiO, and ³⁰SiO were identified in the spectrum of red giant HD 196610 (V*EU Del, spectral class M6 III) taken from the IRTF spectra library. The relative abundance of silicon isotopes in the atmosphere of HD 196610 was estimated by modeling the bands of the first SiO overtone in the stellar spectrum. This abundance turned out to be close (within 3%) to the solar one. At the same time, the carbon isotope ratio ¹²C/¹³C = 6 ± 1 determined by modeling the isotopic components of the first overtone of CO bands suggests that HD 196610 is at an advanced stage of its evolution.

中文翻译：

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后型恒星红外光谱中的SiO谱带

摘要—证明了将SiO吸收在红外光谱中对于后期型恒星的光谱分析的重要性。使用了由ExoMol项目中的J. Tennison组计算出的基本SiO系统的吸收线列表。在从IRTF光谱库中获得的红色巨型HD 196610（V * EU Del，光谱类别M6 III）的光谱中鉴定出了同位素分子²⁸ SiO，²⁹ SiO和³⁰ SiO的能带。HD 196610大气中硅同位素的相对丰度是通过对恒星光谱中第一个SiO泛音的谱带建模来估算的。事实证明这种丰度接近于太阳能丰度（3％之内）。同时碳同位素比¹²C / ¹³ C = 6±1通过对CO波段第一个泛音的同位素成分进行建模而确定，这表明HD 196610处于发展的晚期。