おうし座T型星
The brightness of HD 98800 varies slightly between magnitudes 8.91 and 8.98, and it has been given the variable star designation TV Crateris. The designation TV Crateris includes all four stars and it appears that both components A and B are variable. Component A varies with a period of 2.521 days which is thought to be its rotation period and it is classified as an RS Canum Venaticorum variable, a dwarf star with an uneven surface brightness that changes brightness as it rotates. Component B is thought to be a T Tauri star, a pre-main-sequence star surrounded by a disk. It has been speculated that it is actually a post-T Tauri star and that the variations are caused by irregularities in the tilted disk intercepting the light from the star.