astro.wikisort.org - Asteroid

2815 Soma, provisional designation 1982 RL, is a binary Florian asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 15 September 1982, by American astronomer Edward Bowell at Lowell's Anderson Mesa Station in Flagstaff, Arizona, in the United States .[11] It is named for the mechanical puzzle Soma cube.[3]

2815 Soma

Discovery [1]
Discovered by	E. Bowell
Discovery site	Anderson Mesa Stn.
Discovery date	15 September 1982
Designations
MPC designation	(2815) Soma
Pronunciation	/ˈsoʊmə/[2]
Named after	Soma cube (mechanical puzzle)[3]
Alternative designations	1982 RL · 1955 MH 1970 AC · 1974 DL 1979 XB1
Minor planet category	main-belt · Flora [4]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	61.77 yr (22,562 days)
Aphelion	2.6107 AU
Perihelion	1.8552 AU
Semi-major axis	2.2329 AU
Eccentricity	0.1692
Orbital period (sidereal)	3.34 yr (1,219 days)
Mean anomaly	168.50°
Mean motion	0° 17m 43.44s / day
Inclination	5.7042°
Longitude of ascending node	119.87°
Argument of perihelion	237.53°
Known satellites	1[4][5][6] (Ds/Dp: 0.25±0.02) (orbital period: 17.915 h)
Physical characteristics
Dimensions	6.641±0.105 km[7] 7.067 km[8] 7.07 km (taken)[4] 7.158±0.088 km[9]
Synodic rotation period	2.7327±0.0008 h[lower-alpha 1] 2.73325±0.00007 h[5]
Geometric albedo	0.2273[8] 0.3207±0.0411[9] 0.365±0.083[7]
Spectral type	S [4]
Absolute magnitude (H)	12.49±0.06 (R)[lower-alpha 1] · 12.53±0.02 (R)[5] · 12.6[9] · 12.7[1] · 12.92±0.16[10] · 12.98±0.078[4][8]

Orbit and classification

Soma is a member of the Flora family, a large family of stony asteroids. It orbits the Sun in the inner main-belt at a distance of 1.9–2.6 AU once every 3 years and 4 months (1,219 days). Its orbit has an eccentricity of 0.17 and an inclination of 6° with respect to the ecliptic.[1] It was first identified as 1955 MH at Goethe Link Observatory in 1955. The body's observation arc begins with 1970 AC at Crimea-Nauchnij, 12 years prior to its official discovery at Anderson Mesa.[11]

Diameter and albedo

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer (WISE) with its subsequent NEOWISE mission, Soma measures 6.641 and 7.158 kilometers in diameter and its surface has an albedo of 0.365 and 0.3207, respectively.[7][9] The Collaborative Asteroid Lightcurve Link adopts Peter Pravec's revised WISE-data, that is, an albedo of 0.2273 and a diameter of 7.067 kilometers with an absolute magnitude of 12.98.[4][8]

Moon and lightcurve

Primary

In November 2009, a rotational lightcurve of Soma was obtained from photometric observations by astronomers Petr Pravec, Donald Pray and Peter Kušnirák at Carbuncle Hill Observatory, Rhode Island, and Ondřejov Observatory, in the Czech Republic, respectively. Lightcurve analysis gave a rotation period of 2.7327 hours with a brightness variation of 0.08 magnitude, indicating that the body has a nearly spheroidal shape (U=3-).[lower-alpha 1] The body's spin rate is within the 2.2-to-20 hours range found for most asteroids, about half an hour longer than the so-called fast rotators.

Secondary

In March 2011, photometric observations revealed that Soma is a synchronous binary asteroid with a minor-planet moon orbiting it every 17.915 hours. The system has a secondary-to-primary mean-diameter ratio of 0.25, which means that satellite's diameter measures approximately 25% of that of Soma (the primary), and translate into a diameter of 1.75 kilometers.[5] The observations also gave a refined rotation period for Soma of 2.73325 hours and an amplitude of 0.07 magnitude (U=n.a.). The system has an absolute magnitude of 12.53, and a phase slope parameter (G) of 0.27.[5]

Naming

This minor planet was named for the Soma cube, following a proposal by Belgian astronomer Jean Meeus (also see 2213 Meeus). The Soma cube a dissection puzzle with seven pieces, invented by the Danish mathematician Piet Hein and popularized by American writer Martin Gardner (also see 2587 Gardner).[3] The approved naming citation was published by the Minor Planet Center on 10 September 1984 (M.P.C. 9080).[12]

Notes

References

External links

• CBET No. 2705, Central Bureau for Astronomical Telegrams, 21 April 2011
• (2815) Soma at johnstonsarchive, datasheet, Robert Johnston
• Asteroids with Satellites, Robert Johnston, johnstonsarchive.net
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 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
• 2815 Soma at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 2815 Soma at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

На других языках

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[de] (2815) Soma

(2815) Soma (1982 RL; 1955 MH; 1970 AC; 1974 DL; 1979 XB1) ist ein ungefähr sieben Kilometer großer Asteroid des inneren Hauptgürtels, der am 15. September 1982 vom US-amerikanischen Astronomen Edward L. G. Bowell am Lowell-Observatorium, Anderson Mesa Station (Anderson Mesa) in der Nähe von Flagstaff, Arizona (IAU-Code 688) entdeckt wurde.

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- [en] 2815 Soma

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