CH星是一种特殊的碳星，在它们的光谱上会出现极强的CH吸收带。它们属于第二星族，意思是这些恒星缺少金属，在年龄上也都属于中年以上，并且是低光度的传统C-N碳星。许多CH星都是联星，并且可以合理的相信所有的CH星都是联星。像钡星一样，它们大概也是传统碳星质量转移的结果，现在有一颗白矮星，在现行分类上也属于CH星。

CH stars are particular type of carbon stars which are characterized by the presence of exceedingly strong absorption bands due to CH (methylidyne) in their spectra. They belong to the stellar population II, meaning they're metal poor and generally pretty middle-aged stars, and are under-luminous compared to the classical C–N carbon stars. Many CH stars are known to be binaries, and it's reasonable to believe this is the case for all CH stars. Like Barium stars, they are probably the result of a mass transfer from a former classical carbon star, now a white dwarf, to the current CH-classed star.