Eta Geminorum is a class M3 IIIab star of type SRA. It is a semiregular variable with a period of 233 standard days. It has a class B companion, and the pair is in turn orbited by a distant class G dwarf. It is about 110 parsecs from Earth.
The star is visible from Earth with the naked eye, and has been known since very ancient times. It has many names in different languages: Tejat Prior, Propus, Praepes, Yuè, Pish Pai, η Geminorum, 7 Geminorum, HD 42995, HR 2216, BD+22°1241, HIP 29655, and many others. It is sometimes on the plane of the ecliptic, and so can occasionally be occluded by objects in the solar system.
Its names have various meanings in different cultures. For example, "Pish Pai" is from the Persian for "foreleg", and "Yuè" is from the Pinyin for "battleaxe".
The star Eta Geminorum is called Mapvumia on the sector and subsector maps and listings, because these use the name of the system's principal planet or base.