85 Io


Io (minor planet designation: 85 Io is carbonaceous asteroid from the central region of the asteroid belt, approximately 170 kilometers in diameter. It is an identified Eunomian interloper.

Discovery and naming

It was discovered by C. H. F. Peters on September 19, 1865, and named after Io, a lover of Zeus in Greek mythology. Io is also the name of the volcanic satellite of Jupiter. With a two-digit number and a two-letter name, 85 Io has the shortest designation of all minor planets.

Orbit and physical characteristics

Io is a retrograde rotator, with its pole pointing towards one of ecliptic coordinates = or with a 10° uncertainty. This gives an axial tilt of about 125° or 115°, respectively. Its shape is quite regular.
In the SMASS classification, Io is a carbonaceous C-type asteroid, which means that it is probably a primitive body composed of carbonates. Like 141 Lumen it is an interloper that orbits within the Eunomia asteroid family but it is not related to the shattered parent body.
An Ionian diameter of 178 kilometres was measured from an occultation of a star on December 10, 1995. Another asteroid occultation of Io occurred on March 12, 2009, from the eastern United States, with the star 2UCAC 35694429
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Conjunction to sunstationary, then retrogradeOppositionMinimal distance Maximum brightness stationary, then prograde
27. April 200431.October 200423. December 20041,92017 AE12,3 mag11. February 2005
3.August 20059. January 20065. March 20062,14389 AE 11,8 mag25. April 2006
17.October 200626. April 20079.June 2007 1,38393 AE 12,1 mag26.July 2007
7. March 20086.October 200822.November 20081,61470 AE10,7 mag9. January 2009
8. July 200917. December 200912. February 20102,19864 AE11,1 mag3. April 2010
21. September 201015. March 201130. April 20111,68623 AE12,2 mag20.June 2011
7. January 201231.August 201212.October 20121,28465 AE 11,1 mag19.November 2012
9.June 2013 25.November 201320. January 2014 2,13519 AE10,1 mag12. March 2014
29.August 201410. February 20151. April 20151,95222 AE 12,2 mag22.May 2015
22.November 201530.June 201614.August 2016 1,16222 AE11,6 mag17.September 2016
3.May 2017 3.November 201726. December 2017 1,95048 AE10,2 mag15. February 2018
6.August 201813. January 2019 9. March 20192,12957 AE 11,8 mag 28. April 2019
21.October 20192.May 202014.June 20201,34977 AE 12,0 mag30.July 2020