258 Tyche is a relatively large main belt asteroid discovered in 1886. It is classified as an S-type. Tyche orbits very close to the Eunomia family of asteroids, and could be a member based on composition. However, it is larger than all family members apart from 15 Eunomia while lying at the very edge of the family group. Hence, there is a good chance that it is an unrelated interloper.
There is some uncertainty regarding Tyche's rotation period. Various authors give values from 9.983 to 10.041 hours.
It was discovered by Robert Luther on May 4, 1886 in Düsseldorf and was named after Greek goddess Tyche. Tyche's Roman equivalent is Fortuna, who also has an asteroid named after her (19 Fortuna).
This asteroids perihelion (closest approach to the Sun) is 2AU.