176 Iduna

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176 Iduna
Discovered by C. H. F. Peters
Discovery date October 14, 1877
Minor planet category Main belt
Orbital characteristics[1]
Aphelion 3.714 AU
Perihelion 2.679 AU
Semi-major axis 3.196 AU
Eccentricity 0.162
Orbital period 5.71 years
Inclination 22.54°
Physical characteristics
Dimensions 121 km
Rotation period 11.289[2] hours
Albedo 0.083
Spectral type G
Absolute magnitude (H) 7.90

176 Iduna is a large main-belt asteroid that was discovered by German-American astronomer Christian Heinrich Friedrich Peters on October 14, 1877, in Clinton, New York. It is named after the Ydun, a club in Stockholm that hosted an astronomical conference. A G-type asteroid, it has a composition similar to that of the largest main-belt asteroid, 1 Ceres.

An occultation of a star by Iduna was observed from Mexico on January 17, 1998.

Photometric observations of this asteroid at the Romer Observatory in Aarhus, Denmark during 1996 gave a light curve with a period of 11.289 ± 0.006 hours and a brightness variation of 0.35 in magnitude.[2] A 2008 study at the Palmer Divide Observatory in Colorado Springs, Colorado gave a period of 11.309 ± 0.005 hours, confirming the 1996 result.[3]


  1. ^ Yeomans, Donald K., "176 Iduna", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-03-30. 
  2. ^ a b Hansen, A. T.; Arentoft, T. (June 1997), "The Rotational Period of 176 Iduna", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers 24: 14, Bibcode:1997MPBu...24Q..14H. 
  3. ^ Warner, Brian D. (June 2008), "Asteroid Lightcurve Analysis at the Palmer Divide Observatory - June - October 2007", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers 35 (2): 56–60, Bibcode:2008MPBu...35...56W.