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Wikipedia / 85 Io

85 Io is a carbonaceous asteroid in 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 19 September 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 (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 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 10 December 1995. Another asteroid occultation of Io (magnitude 13.2) occurred on 12 March 2009, from the eastern United States, with the star 2UCAC 35694429 (magnitude 13.8).

Conjunction to sun

stationary, then retrograde

Opposition

Minimal distance (AE)

Maximum brightness (mag)

stationary, then prograde

27. April 2004

31.October 2004

23. December 2004

1,92017 AE

12,3 mag

11. February 2005

3.August 2005

9. January 2006

5. March 2006

2,14389 AE

11,8 mag

25. April 2006

17.October 2006

26. April 2007

9.June 2007

1,38393 AE

12,1 mag

26.July 2007

7. March 2008

6.October 2008

22.November 2008

1,61470 AE

10,7 mag

9. January 2009

8. July 2009

17. December 2009

12. February 2010

2,19864 AE

11,1 mag

3. April 2010

21. September 2010

15. March 2011

30. April 2011

1,68623 AE

12,2 mag

20.June 2011

7. January 2012

31.August 2012

12.October 2012

1,28465 AE

11,1 mag

19.November 2012

9.June 2013

25.November 2013

20. January 2014

2,13519 AE

10,1 mag

12. March 2014

29.August 2014

10. February 2015

1. April 2015

1,95222 AE

12,2 mag

22.May 2015

22.November 2015

30.June 2016

14.August 2016

1,16222 AE

11,6 mag

17.September 2016

3.May 2017

3.November 2017

26. December 2017

1,95048 AE

10,2 mag

15. February 2018

6.August 2018

13. January 2019

9. March 2019

2,12957 AE

11,8 mag

28. April 2019

21.October 2019

2.May 2020

14.June 2020

1,34977 AE

12,0 mag

30.July 2020

See also

Notes

References