Astronomy:7958 Leakey

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7958 Leakey
Discovery [1]
Discovered byC. S. Shoemaker
E. M. Shoemaker
Discovery sitePalomar Obs.
Discovery date5 June 1994
Designations
(7958) Leakey
Named afterLeakey family
(Mary, Louis, Richard)[2]
1994 LE3 · 1991 GT
Minor planet categorymain-belt · Hungaria [3][4]    
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc31.09 yr (11,355 days)
|{{{apsis}}}|helion}}2.0211 AU
|{{{apsis}}}|helion}}1.7329 AU
1.8770 AU
Eccentricity0.0768
Orbital period2.57 yr (939 days)
Mean anomaly296.31°
Inclination21.973°
Longitude of ascending node195.74°
154.20°
Known satellites1 [5][6][lower-alpha 1][lower-alpha 2]
Physical characteristics
Dimensions2.94±0.17 km[7]
3.35 km (calculated)[4]
Rotation period2.34831±0.00003 h[lower-alpha 2]
2.34843±0.00006 h[6][lower-alpha 1]
Geometric albedo0.30 (assumed)[4]
0.468±0.073[7]
E [4]
Absolute magnitude (H)14.3[1][4]


7958 Leakey, provisional designation 1994 LE3, is a Hungaria asteroid and synchronous binary system from the inner regions of the asteroid belt, approximately 3 kilometers in diameter.

It was discovered on 5 June 1994, by American astronomer-couple Carolyn and Eugene Shoemaker at the Palomar Observatory in California, United States.[3] Its minor-planet moon was discovered in 2012. The asteroid was named after the members of the Leakey family: Mary, Louis and Richard.[2]

Orbit and classification

Leakey is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun in the inner main-belt at a distance of 1.7–2.0 AU once every 2 years and 7 months (939 days). Its orbit has an eccentricity of 0.08 and an inclination of 22° with respect to the ecliptic.[1]

Physical characteristics

Leakey is an assumed E-type asteroid.[4]

Lightcurves

In 2012, and 2015, several lightcurves of Leakey were obtained by astronomers Brian Warner, Robert Stephens and Daniel Coley. Lightcurve analysis gave a concurring and well-defined rotation period of 2.35 hours with a brightness variation between 0.19 and 0.22 magnitude ({{{1}}}).[6][lower-alpha 1][lower-alpha 2][lower-alpha 3]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Leakey measures 2.94 kilometers in diameter and its surface has a high albedo of 0.468.[7]

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.30 – a compromise value between 0.4 and 0.2, corresponding to the Hungaria asteroids both as family and orbital group – and calculates a diameter of 3.35 kilometers based on an absolute magnitude of 14.3.[4]

Moon

The 2012-photometric lightcurve observation also revealed, that Leakey is a synchronous binary asteroid with a minor-planet moon orbiting it every 50.24 hours.[5][6][lower-alpha 1] The moon (secondary) was designated S/2012 (7958) 1.

It is likely that the secondary body is tidally locked, which means that its rotation is synchronous with its orbital period. Based on only two observations at the Palmer Divide Observatory (716), it is tentatively estimated that the size-ratio of the binary system is 0.3±0.03, which would give a 1-kilometer diameter for the satellite.[6]

Naming

The minor planet is named after the Leakey's, a family of Kenyan paleoanthropologists: Mary Leakey (1913–1996), her husband Louis Leakey (1903–1972), and their son Richard Leakey (born 1944). Working for many years in Tanzania and Kenya, they conclusively proved that human evolution began in Africa rather than Asia. Richard explored the Koobi Fora archaeological site in Kenya, where many Hominin fossils have been found.[2] The approved naming citation was published by the Minor Planet Center on 11 April 1998 (M.P.C. 31612).[8]

Notes

  1. ↑ 1.0 1.1 1.2 1.3 Warner (2012): Lightcurve plot of 7958 Leakey and its minor-planet moon (second plot) at the Palmer Divide Observatory, B. D. Warner (2012)
  2. ↑ 2.0 2.1 2.2 Stephens (2015): lightcurve plot of (7958) Leakey with rotation period 2.34831±0.00003 hours and a brightness amplitude of 0.19 mag. Summary figures at Collaborative Asteroid Lightcurve Link (CALL)
  3. ↑ Daniel Coley (2012): lightcurve plot of (7958) Leakey, at the Center for Solar System Studies (CS3).

References

  1. ↑ 1.0 1.1 1.2 1.3 "JPL Small-Body Database Browser: 7958 Leakey (1994 LE3)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007958. 
  2. ↑ 2.0 2.1 2.2 Schmadel, Lutz D. (2007). "(7958) Leakey". Dictionary of Minor Planet Names – (7958) Leakey. Springer Berlin Heidelberg. p. 625. doi:10.1007/978-3-540-29925-7_6763. ISBN 978-3-540-00238-3. 
  3. ↑ 3.0 3.1 "7958 Leakey (1994 LE3)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=7958. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 "LCDB Data for (7958) Leakey". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=7958%7CLeakey. 
  5. ↑ 5.0 5.1 Johnston, Robert. "(7958) Leakey". http://www.johnstonsarchive.net/astro/astmoons/am-07958.html. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 Warner, Brian D.; Coley, Daniel; Harris, Alan W. (October 2012). "Lightcurve for 7958 Leakey: A New Hungaria Binary". The Minor Planet Bulletin 39 (4): 240–241. ISSN 1052-8091. Bibcode: 2012MPBu...39..240W. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012MPBu...39..240W. Retrieved 17 December 2015. 
  7. ↑ 7.0 7.1 7.2 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C. et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters 759 (1): 5. doi:10.1088/2041-8205/759/1/L8. Bibcode: 2012ApJ...759L...8M. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012ApJ...759L...8M. Retrieved 4 December 2016. 
  8. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html. 

External links



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