249 Ilse

249 Ilse

Discovery
Discovered by	C. H. F. Peters
Discovery date	16 August 1885
Designations
Alternative names	1973 PB
Minor planet category	Main belt
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	130.59 yr (47699 d)
Aphelion	2.89450 AU (433.011 Gm)
Perihelion	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° 16^m 8.065^s / day
Inclination	9.61979°
Longitude of ascending node	334.727°
Argument of perihelion	42.3241°
Earth MOID	0.871134 AU (130.3198 Gm)
Jupiter MOID	2.6098 AU (390.42 Gm)
Jupiter Tisserand parameter	3.490
Physical characteristics
Dimensions	34.83±1.1 km
Mass	unknown
Mean density	unknown
Equatorial surface gravity	unknown
Equatorial escape velocity	unknown
Rotation period	84.94 h (3.539 d)
Geometric albedo	0.0428±0.003
Temperature	unknown
Spectral type	unknown
Absolute magnitude (H)	11.33

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 German 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.^[2]

References

1. "249 Ilse". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 12 May 2016.
2. Johnston, Robert. "Other Reports of Asteroid/TNO Companions (Updated 13 July 2013)". Retrieved 19 November 2013.

• The Asteroid Orbital Elements Database
• Minor Planet Discovery Circumstances
• Asteroid Lightcurve Data File

External links

• 249 Ilse at the JPL Small-Body Database
  
  • Discovery · Orbit diagram · Orbital elements · Physical parameters