9 Metis

9 Metis
Discovery
Discovered byA. Graham
Discovery date25 April 1848
Designations
(9) Metis
Pronunciation/ˈmtɪs/[1]
Named after
Mētis
1974 QU2
Main belt
AdjectivesMetidian /mɛˈtɪdiən/
Symbol (historical)
Orbital characteristics[2]
Epoch 13 September 2023
(JD 2453300.5)
Aphelion2.68 AU (401 million km)
Perihelion2.093 AU (313.1 million km)
2.387 AU (357.1 million km)
Eccentricity0.1231
3.69 yr (1346.74 d)
345.43°
Inclination5.577°
68.87°
6 November 2023
5.75°
Earth MOID1.1 AU (160 million km)
Proper orbital elements[3]
2.3864354 AU
0.1271833
4.6853629°
97.638314 deg / yr
3.68708 yr
(1346.705 d)
Precession of perihelion
38.754973 arcsec / yr
Precession of the ascending node
−41.998090 arcsec / yr
Physical characteristics
Dimensions(222 × 182 × 130) ± 12 km[4]
173±2 km[5]
190±? km (Dunham)[2]
Flattening0.39[a]
Mass(8.0±1.9)×1018 kg[5]
(11.3±2.2)×1018 kg[b][4]
Mean density
2.94±0.70 g/cm3[5]
4.12±1.17 g/cm3[4]
0.2116 d (5.079 h)[2]
0.18[5]
0.118[2]
Temperaturemax: 282 K (+9 °C)[6]
S[7]
8.1[8] to 11.83
6.33[2]
0.23" to 0.071"

9 Metis is one of the larger main-belt asteroids. It is composed of silicates and metallic nickel-iron, and may be the core remnant of a large asteroid that was destroyed by an ancient collision.[9] Metis is estimated to contain just under half a percent of the total mass of the asteroid belt.[10]

Metis passed within 0.034 AU, or 5,000,000 kilometres (3,100,000 mi), of Vesta on 19 August 2004.[11]

  1. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  2. ^ a b c d e "JPL Small-Body Database Browser: 9 Metis" (last observation: 2023-08-13). Retrieved 18 September 2023.
  3. ^ "AstDyS-2 Metis Synthetic Proper Orbital Elements". Department of Mathematics, University of Pisa, Italy. Retrieved 1 October 2011.
  4. ^ a b c James Baer, Steven Chesley & Robert Matson (2011) "Astrometric masses of 26 asteroids and observations on asteroid porosity." The Astronomical Journal, Volume 141, Number 5
  5. ^ a b c d e P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
  6. ^ L. F. Lim et al., Thermal infrared (8–13 μm) spectra of 29 asteroids: the Cornell Mid-Infrared Asteroid Spectroscopy (MIDAS) Survey, Icarus Vol. 173, p. 385 (2005).
  7. ^ asteroid lightcurve data file (March 2001)
  8. ^ Donald H. Menzel & Jay M. Pasachoff (1983). A Field Guide to the Stars and Planets (2nd ed.). Boston, MA: Houghton Mifflin. pp. 391. ISBN 0-395-34835-8.
  9. ^ Kelley, Michael S; Michael J. Gaffey (2000). "9 Metis and 113 Amalthea: A Genetic Asteroid Pair". Icarus. 144 (1): 27–38. Bibcode:2000Icar..144...27K. doi:10.1006/icar.1999.6266.
  10. ^ Jim Baer (2010). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on 2 July 2013. Retrieved 13 February 2011.
  11. ^ "JPL Close-Approach Data: 9 Metis". 15 March 2009. Retrieved 6 May 2009.


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