Stellar vampirism

Stellar vampirism is an astronomical phenomenon in which a star (usually O-type), known as a "vampire star," in a binary system attracts the mass of another.^[1][2] As stars age in binary systems, they can grow past the threshold at which their gravity protects them from their companion.^[1] The process of stellar vampirism results in the "vampire star" having an extended life. The "victim" star is left with its core exposed, which mimics the appearance of a much younger star. An example of a star system exhibiting stellar vampirism is HR 6819.^[2][3][4][5]