85 Io is a big, dark Main belt asteroid of the C spectral class. It is probably a primitive body made of carbonates. Like 70 Panopaea it orbits within the Eunomia asteroid family but it is not related to the shattered parent body.
Io is a retrograde rotator, with its pole pointing towards one of ecliptic coordinates (β, λ) = (-45°, 105°) or (-15°, 295°) with a 10° uncertainty. This gives an axial tilt of about 125° or 115°, respectively. Its shape is quite spherical.
It was found by C. H. F. Peters on September 19, 1865 and named after Io, a lover of Zeus in Greek mythology.
A diameter of 178 kilometres was measured from an occultation of a star on December 10, 1995 .
Io is also the name of the volcanic moon of Jupiter. With a two-digit number and a two-letter name, 85 Io has the shortest designation of all minor planets.
Other websites [change]
- PDS lightcurve data
A. Erikson Photometric observations and modelling of the asteroid 85 Io in conjunction with data from an occultation event during the 1995-96 apparition, Planetary and Space Science, Vol. 47, p. 327 (1999).
G. A. Krasinsky et al. Hidden Mass in the Asteroid Belt, Icarus, Vol. 158, p. 98 (2002).