Astronomy:93 Minerva

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Short description: Main-belt asteroid
93 Minerva
93Minerva (Lightcurve Inversion).png
A three-dimensional model of 93 Minerva based on its light curve.
Discovery
Discovered byJames Craig Watson
Discovery siteAnn Arbor, Michigan
Discovery date24 August 1867
Designations
(93) Minerva
Pronunciation/mɪˈnɜːrvə/[1]
Named afterMinerva
1949 QN2, A902 DA
Minor planet categoryMain belt
AdjectivesMinervian, Minervean /mɪˈnɜːrviən/
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc146.14 yr (53379 d)
|{{{apsis}}}|helion}}3.1429 astronomical unit|AU (470.17 Gm)
|{{{apsis}}}|helion}}2.3711 AU (354.71 Gm)
2.7570 AU (412.44 Gm)
Eccentricity0.13998
Orbital period4.58 yr (1672.0 d)
Average Orbital speed~17.86 km/s
Mean anomaly262.022°
Mean motion0° 12m 55.116s / day
Inclination8.56143°
Longitude of ascending node4.06265°
274.543°
Physical characteristics
Dimensions141.55±4.0 km (IRAS)[2]
156km (spherical)[3]
Mass3.7×1018 kg (assumed)[4]
Mean density1.9 g/cm3[3]
Equatorial surface gravity
4.139 cm/s2 (0.004221 g)[5]
Equatorial escape velocity
8.035 cm/s[5]
Rotation period5.982 h (0.2493 d)[2]
Geometric albedo0.0733±0.004[2]
C[2]
G?[3]
Absolute magnitude (H)8.0[2]


Minerva (minor planet designation: 93 Minerva) is a large trinary main-belt asteroid. It is a C-type asteroid, meaning that it has a dark surface and possibly a primitive carbonaceous composition. It was discovered by J. C. Watson on 24 August 1867, and named after Minerva, the Roman equivalent of Athena, goddess of wisdom. An occultation of a star by Minerva was observed in France , Spain and the United States on 22 November 1982. An occultation diameter of ~170 km was measured from the observations. Since then two more occultations have been observed, which give an estimated mean diameter of ~150 km for diameter.[6][7]

Satellites

On 16 August 2009, at 13:36 UT, the Keck Observatory's adaptive optics system revealed that the asteroid 93 Minerva possesses 2 small moons.[8] They are 4 and 3 km in diameter and the projected separations from Minerva correspond to 630 km (8.8 x Rprimary) and 380 km (5.2 x Rprimary) respectively.[8] They have been named Aegis[9] (/ˈɪs/)[10] and Gorgoneion[9] (/ˌɡɔːrɡəˈnən/).[11]

References

  1. Noah Webster (1884) A Practical Dictionary of the English Language
  2. 2.0 2.1 2.2 2.3 2.4 2.5 "JPL Small-Body Database Browser: 93 Minerva". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=93. 
  3. 3.0 3.1 3.2 Franck Marchis (7 October 2011). "Is the triple Asteroid Minerva a baby-Ceres?". NASA blog (Cosmic Diary). http://cosmicdiary.org/fmarchis/2011/10/07/the-secrets-of-asteroid-minerva-and-its-two-moons/. 
  4. Using a spherical radius of 78 km; volume of a sphere * density of 1.9 g/cm3 yields a mass (m=d*v) of 3.77E+18 kg
  5. 5.0 5.1 "HEC:Exoplanets Calculator/Planet Density, Surface Gravity, and Escape Velocity". Planetary Habitability Laboratory. University of Puerto Rico at Arecibo. http://phl.upr.edu/projects/habitable-exoplanets-catalog/calculators. 
  6. Millis, R.L; Wasserman, L.H; Bowell, E; Franz, O.G; Nye, R; Osborn, W; Klemola, A (1985), "The occultation of AG+29°398 by 93 Minerva", Icarus 61 (1): 124–131, doi:10.1016/0019-1035(85)90159-9, Bibcode1985Icar...61..124M 
  7. "Observed minor planet occultation events". astro.cz. 26 July 2005. http://mpocc.astro.cz/world/mpocc1.txt. 
  8. 8.0 8.1 Franck Marchis (2009-08-21). "The discovery of a new triple asteroid, (93) Minerva". Cosmic Diary Blog. http://cosmicdiary.org/fmarchis/2009/08/21/the-discovery-of-a-new-triple-asteroid-93-minerva/. 
  9. 9.0 9.1 Franck Marchis (2013-12-26). "Asteroid Minerva finds its magical weapons in the sky". The Planetary Society. https://www.planetary.org/articles/20131224-asteroid-minerva-finds-its-magical-weapons-in-the-sky. 
  10. "aegis". aegis. Oxford University Press. http://www.lexico.com/definition/aegis. 
  11. "gorgoneion". gorgoneion. Oxford University Press. http://www.lexico.com/definition/gorgoneion. 

External links