Draco C1 is a known symbiotic binary star system composed of a carbon red giant and a hot, compact companion—likely a white dwarf—belonging to the Draco dwarf spheroidal galaxy. From near-infrared spectroscopic observations taken by the Apache Point Observatory Galactic Evolution Experiment (APOGEE-2), part of Sloan Digital Sky Survey IV, we provide updated stellar parameters for the cool, giant component, and constrain the temperature and mass of the hot, compact companion. Prior measurements of the periodicity of the system, based on only a few epochs of radial velocity data or relatively short baseline photometric observations, were sufficient only to place lower limits on the orbital period ( P > 300 days). For the first time, we report precise orbital parameters for the binary system: with 43 radial velocity measurements from APOGEE spanning an observational baseline of more than 3 yr, we definitively derive the period of the system to be ##IMG## {$...}

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Draco C1共生二进制的几何

德拉科C1是已知的共生双星系统，由碳红巨星和热紧凑的同伴（可能是白矮星）组成，属于德拉科矮球体星系。根据斯隆数字天空调查IV的一部分，阿帕奇点天文台银河演化实验（APOGEE-2）进行的近红外光谱观察，我们提供了更新的恒星参数，用于冷却巨大的组件，并限制了高温和高温的质量，紧凑的伴侣。仅基于径向速度数据的几个时期或相对较短的基线光度学观测值，对系统周期性的先前测量仅足以对轨道周期设置下限（P> 300天）。首次，我们报告了二进制系统的精确轨道参数：