11885 Summanus

11885 Summanus

Discovery[1]
Discovered by	Spacewatch
Discovery site	Kitt Peak southwest of Tucson, Arizona, USA
Discovery date	25 September 1990
Designations
MPC designation	1990 SS
Alternative names	MPO 196501
Minor planet category	Apollo NEO
Orbital characteristics[2]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc	7504 days (20.54 yr)
Aphelion	2.511961332 AU (375.7840665 Gm)
Perihelion	0.894558836 AU (133.8240971 Gm)
Semi-major axis	1.703260084 AU (254.8040818 Gm)
Eccentricity	0.47479610
Orbital period	2.22 yr (811.93 d)
Average orbital speed	21.4743560 km/s
Mean anomaly	80.7443653°
Mean motion	0° 26^m 36.192^s / day
Inclination	19.4198168°
Longitude of ascending node	359.890291°
Argument of perihelion	116.070841°
Earth MOID	0.067275 AU (10.0642 Gm)
Jupiter MOID	2.77022 AU (414.419 Gm)
Jupiter Tisserand parameter	4.005
Physical characteristics
Dimensions	530–1200 m[3]
Rotation period	7.358 h (0.3066 d)
Sidereal rotation period	7.358 h[2]
Absolute magnitude (H)	18.5[2]

11885 Summanus (also designated 1990 SS) is an asteroid that is a Near-Earth Object (NEO) and an Apollo asteroid.

Discovery and naming

11885 Summanus was discovered by Spacewatch on September 25, 1990, the first fully automatic discovery of a near-Earth asteroid.^[4][5] The name Summanus is symbolic of the discovery of the asteroid by software running on a (lightning-fast) computer.^[1]

Orbit

The orbit is well-established with over 20 years of observations. The closest approach to the Earth in the years 1900–2200 is 0.102 AU (15,300,000 km; 9,500,000 mi) on March 17, 1991, and March 17, 2011. For comparison, the distance to the Moon is about 0.0026 AU (390,000 km; 240,000 mi).

References

1. "(11885) Summanus = 1990 SS". Minor Planet Center. 2011-04-12.
2. "JPL Small-Body Database Browser: 11885 Summanus (1990 SS)" (last observation: 2011-04-12; arc: 7504 days). Jet Propulsion Laboratory. Retrieved 9 April 2016.
3. "ABSOLUTE MAGNITUDE (H)". NASA.
4. "Twentieth Anniversary of the First Automatic Discovery of a Near-Earth Asteroid by Software -- Spacewatch Project". Spacewatch. September 25, 2010.
5. James V. Scotti (1993). Asteroids, Comets, Meteors 1993: Proceedings of the 160th Symposium of the International Astronomical Union, Held in Belgirate, Italy, June 14–18, 1993. Springer Science & Business Media (2012). p. 21. ISBN 9789401111485.

External links

• 11885 Summanus at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters