astro.wikisort.org - Asteroid

1928 Summa, provisional designation 1938 SO, is a stony asteroid from the inner regions of the asteroid belt, approximately 9 kilometers in diameter.

1928 Summa

Discovery[1]
Discovered by	Y. Väisälä
Discovery site	Turku Obs.
Discovery date	21 September 1938
Designations
MPC designation	(1928) Summa
Named after	Finnish village (Battle of Summa)[2]
Alternative designations	1938 SO · 1969 PA
Minor planet category	main-belt · (inner)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	78.38 yr (28,628 days)
Aphelion	2.9797 AU
Perihelion	1.9733 AU
Semi-major axis	2.4765 AU
Eccentricity	0.2032
Orbital period (sidereal)	3.90 yr (1,423 days)
Mean anomaly	98.003°
Mean motion	0° 15m 10.44s / day
Inclination	4.5756°
Longitude of ascending node	180.42°
Argument of perihelion	157.80°
Physical characteristics
Dimensions	8.34 km (derived)[3] 9.333±0.170 km[4][5]
Synodic rotation period	6.8549±0.0006 h[6] 6.855±0.001 h[7] 9.66 h (dated)[8]
Geometric albedo	0.160±0.043[4][5] 0.20 (assumed)[3]
Spectral type	S[3][8] B–V = 1.010[1]
Absolute magnitude (H)	12.68[1] · 12.76[3][4][8] · 13.20±0.85[9]

It was discovered on 21 September 1938, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland.[10] It was named for a Finnish village where the Battle of Summa took place.[2]

Orbit and classification

Summa is a S-type asteroid that orbits the Sun in the inner main-belt at a distance of 2.0–3.0 AU once every 3 years and 11 months (1,423 days). Its orbit has an eccentricity of 0.20 and an inclination of 5° with respect to the ecliptic.[1] The body's observation arc begins at Turku one night after its official discovery observation, with no precoveries taken, and no prior identifications made.[10]

Rotation period

In March 1984, the first but poorly rated rotational lightcurve of Summa was obtained from photometric observations by American astronomer Richard Binzel. It gave a rotation period of 9.66 hours with a brightness amplitude of 0.14 magnitude (U=1).[8]

In August 2012, a refined yet ambiguous lightcurve with a period of 6.855 hours and an amplitude of 0.13 was obtained by Larry E. Owings at the Barnes Ridge Observatory in California (U=2+). Lightcurve analysis also considered that Summa might be a binary system.[7] One month later, the so-far best rated lightcurve from British astronomer Kevin Hills using the remote controlled Riverland Dingo Observatory in Australia, gave a period of 6.8549 hours with a brightness amplitude of 0.18 (U=3).[6]

Diameter an albedo

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Summa measures 9.333 kilometers in diameter and its surface has an albedo of 0.160,[4][5] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 8.34 kilometers with an absolute magnitude of 12.76.[3]

Naming

This minor planet was named after the village on the Karelian Isthmus, where the Battle of Summa took place during the Finnish Winter War (1939–1940).[2] The approved naming citation was published by the Minor Planet Center on 1 August 1980 (M.P.C. 5450).[11] Most of Yrjö Väisälä's discoveries have names that relate in one way or another to this military conflict between Finland and the Soviet Union during World War II.

References

External links

• (1928) Summa Archived 5 March 2016 at the Wayback Machine, lightcurve at Hills Observatory, Kevin Hills
• Kevin Hills, Asteroid hunter realizes life's dreams at GRAS, Remote asteroid hunting from the UK, July 2009
• Asteroid Lightcurve Database (LCDB), query form (info Archived 21 July 2011 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 1928 Summa at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 1928 Summa at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

На других языках

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[de] (1928) Summa

(1928) Summa ist ein Asteroid des Hauptgürtels, der am 21. September 1938 von dem finnischen Astronomen Yrjö Väisälä in Turku entdeckt wurde.

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- [en] 1928 Summa

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