Astronomy:249 Ilse

Short description: Main-belt asteroid

249 Ilse

3D model based on lightcurve data
Discovery
Discovered by	C. H. F. Peters
Discovery date	16 August 1885
Designations
MPC designation	(249) Ilse
Pronunciation	German: [ˈɪlzə]
Named after	Ilse
Alternative designations	A885 QA, 1973 PB
Minor planet category	Main belt
Orbital characteristics
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	130.59 yr (47699 d)
|{{{apsis}}}|helion}}	2.89450 astronomical unit|AU (433.011 Gm)
|{{{apsis}}}|helion}}	1.85992 AU (278.240 Gm)
Semi-major axis	2.37721 AU (355.626 Gm)
Eccentricity	0.21760
Orbital period	3.67 yr (1338.8 d)
Average Orbital speed	19.31 km/s
Mean anomaly	223.964°
Mean motion	0° 16m 8.065s / day
Inclination	9.61979°
Longitude of ascending node	334.727°
|{{{apsis}}}|helion}}	42.3241°
Physical characteristics
Dimensions	34.83±1.1 km
Rotation period	84.94 h (3.539 d)
Geometric albedo	0.0428±0.003
Physics	unknown
Absolute magnitude (H)	11.33

Ilse (minor planet designation: 249 Ilse) is a Main belt asteroid. It has an unusually slow rotation period, about 3.5 days.

It was discovered by C. H. F. Peters on August 16, 1885, in Clinton, New York and was named after Ilse, a legendary Germany princess.

Due to the long rotation period, a possible asteroidal satellite of Ilse was proposed by R. P. Binzel in 1987 however no evidence of this has been found.

External links

• The Asteroid Orbital Elements Database
• Minor Planet Discovery Circumstances
• Asteroid Lightcurve Data File
• 249 Ilse at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 249 Ilse at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters