en 176 Iduna

176 Iduna
	3D convex shape model of 176 Iduna
Discovery
Discovered by	C. H. F. Peters
Discovery date	14 October 1877
Designations
MPC designation	(176) Iduna
Pronunciation	/iːˈduːnə/
Named after	Iðunn
Alternative designations	A877 TB; 1945 RQ
Minor planet category	Main belt
Orbital characteristics
	Epoch 31 July 2016 (JD 2457600.5)
	Uncertainty parameter 0
Observation arc	138.50 yr (50587 d)
Aphelion	3.7235 AU (557.03 Gm)
Perihelion	2.6526 AU (396.82 Gm)
Semi-major axis	3.1880 AU (476.92 Gm)
Eccentricity	0.16796
Orbital period (sidereal)	5.69 yr (2079.1 d)
Mean anomaly	165.15°
Mean motion	0° 10m 23.34s / day
Inclination	22.660°
Longitude of ascending node	200.50°
Argument of perihelion	188.17°
Earth MOID	1.65682 AU (247.857 Gm)
Jupiter MOID	1.73015 AU (258.827 Gm)
TJupiter	3.056
Physical characteristics
Dimensions	121.04±2.2 km
Synodic rotation period	11.2877 h (0.47032 d); 11.289 hours
Geometric albedo	0.0834±0.003
Spectral type	G
Absolute magnitude (H)	8.2

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 Sällskapet Idun, a club in Stockholm that hosted an astronomical conference; Idun (Iðunn, Iduna) is also a Norse goddess.^[3]^[4] 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.^[5]

References

^ ^a ^b Yeomans, Donald K., "176 Iduna", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
^ ^a ^b Hansen, A. T.; Arentoft, T. (June 1997), "The Rotational Period of 176 Iduna", The Minor Planet Bulletin, 24: 14, Bibcode:1997MPBu...24Q..14H.
^ "Motiveringar till asteroidnamn med svensk anknytning" (in Swedish). Uppsala University. Archived from the original on 8 July 2009. Retrieved 24 October 2017.
^ Schmadel, Lutz (1992). Dictionary of Minor Planet Names. Vol. 2. Berlin: Springer Verlag. p. 28. ISBN 3-540-00238-3. Retrieved 24 October 2017.
^ Warner, Brian D. (June 2008), "Asteroid Lightcurve Analysis at the Palmer Divide Observatory - June - October 2007", The Minor Planet Bulletin, 35 (2): 56–60, Bibcode:2008MPBu...35...56W.