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11885 Summanus

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11885 Summanus
Discovery[1]
Discovered bySpacewatch
Discovery siteKitt Peak Obs.
Discovery date25 September 1990
Designations
1990 SS
Pronunciation/sʌˈmnəs/[2]
Named after
Summānus
NEO · Apollo[3]
Orbital characteristics[3]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc20.54 yr (7,504 days)
Aphelion2.5119 AU
Perihelion0.8950 AU
1.7035 AU
Eccentricity0.4746
2.22 yr (812 days)
346.75°
0° 26m 35.88s / day
Inclination19.419°
359.89°
116.07°
Earth MOID0.0689 AU (26.8 LD)
Physical characteristics
1.298±0.446 km[3]
7.358 h[4]
0.033±0.029[3]
18.5[3]

11885 Summanus (prov. designation: 1990 SS) is a dark asteroid and large near-Earth object of the Apollo group. It was discovered by astronomers with the Spacewatch programm at Kitt Peak Observatory on 25 September 1990. The object has a rotation period of 7.3 hours and measures approximately 1.3 kilometers (0.8 miles) in diameter.[3] It was named after Summanus, the Roman deity of nocturnal lightning and thunder.[1]

Discovery and naming

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Summanus was discovered on 25 September 1990, by Spacewatch survey at the Kitt Peak Observatory, southwest of Tucson, Arizona, United States. It was the first fully automatic discovery of a near-Earth asteroid.[5][6] The name Summanus is symbolic of the discovery of the asteroid by software running on a (lightning-fast) computer.[1]

Orbit

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The orbit is well-established with over 20 years of observations. Summanus orbits the Sun in the inner main-belt at a distance of 0.9–2.5 AU once every 2 years and 3 months (812 days). Its orbit has an eccentricity of 0.47 and an inclination of 19° with respect to the ecliptic.[3]

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

References

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  1. ^ a b c "11885 Summanus (1990 SS)". Minor Planet Center. Retrieved 2 November 2017.
  2. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  3. ^ a b c d e f g "JPL Small-Body Database Browser: 11885 Summanus (1990 SS)" (2011-04-12 last obs.). Jet Propulsion Laboratory. Archived from the original on 27 July 2020. Retrieved 2 November 2017.
  4. ^ "LCDB Data for (11885) Summanus". Asteroid Lightcurve Database (LCDB). Retrieved 2 November 2017.
  5. ^ "Twentieth Anniversary of the First Automatic Discovery of a Near-Earth Asteroid by Software -- Spacewatch Project". Spacewatch. 25 September 2010. Archived from the original on 22 September 2015. Retrieved 9 June 2015.
  6. ^ 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.
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