 | |
| Discovery | |
|---|---|
| Discovered by | A. Graham |
| Discovery date | 25 April 1848 |
| Designations | |
| (9) Metis | |
| Pronunciation | /ˈmiːtɪs/[1] |
Named after | Mētis |
| 1974 QU2 | |
| Main belt | |
| Adjectives | Metidian /mɛˈtɪdiən/ |
| Symbol | .svg){kind=small} (historical) |
| Orbital characteristics[2] | |
| Epoch 13 September 2023 (JD 2453300.5) | |
| Aphelion | 2.68 AU (401 million km) |
| Perihelion | 2.093 AU (313.1 million km) |
| 2.387 AU (357.1 million km) | |
| Eccentricity | 0.1231 |
| 3.69 yr (1346.74 d) | |
| 345.43° | |
| Inclination | 5.577° |
| 68.87° | |
| 6 November 2023 | |
| 5.75° | |
| Earth MOID | 1.1 AU (160 million km) |
| Proper orbital elements[3] | |
Proper semi-major axis | 2.3864354 AU |
Proper eccentricity | 0.1271833 |
Proper inclination | 4.6853629° |
Proper mean motion | 97.638314 deg / yr |
Proper orbital period | 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] | |
| Flattening | 0.39[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] | |
| Temperature | max: 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]
- ^ Noah Webster (1884) A Practical Dictionary of the English Language
- ^ a b c d e "JPL Small-Body Database Browser: 9 Metis" (last observation: 2023-08-13). Retrieved 18 September 2023.
- ^ "AstDyS-2 Metis Synthetic Proper Orbital Elements". Department of Mathematics, University of Pisa, Italy. Retrieved 1 October 2011.
- ^ 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
- ^ 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
- ^ 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).
- ^ asteroid lightcurve data file (March 2001)
- ^ 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.
- ^ 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.
- ^ Jim Baer (2010). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on 2 July 2013. Retrieved 13 February 2011.
- ^ "JPL Close-Approach Data: 9 Metis". 15 March 2009. Retrieved 6 May 2009.
Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).