423 Diotima

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423 Diotima
423Diotima (Lightcurve Inversion).png
A three-dimensional model of 423 Diotima based on its light curve.
Discovery
Discovered by Auguste Charlois
Discovery date December 7, 1896
Designations
Pronunciation /d.əˈtmə/
Named after Diotima of Mantinea
Alternative names 1896 DB
Minor planet category Main belt (Eos)
Orbital characteristics
Epoch 30 January 2005 (JD 2453400.5)
Aphelion 477.421 Gm (3.191 AU)
Perihelion 439.945 Gm (2.941 AU)
Semi-major axis 458.683 Gm (3.066 AU)
Eccentricity 0.041
Orbital period 1960.969 d (5.37 a)
Average orbital speed 17.01 km/s
Mean anomaly 179.514°
Inclination 11.24°
Longitude of ascending node 69.564°
Argument of perihelion 207.473°
Physical characteristics
Dimensions 208.8 ± 4.9 km (IRAS)[1]
171 x 138 km[2]
211.64 ± 16.02[3] km
Mass 1.6×1019 kg[4][5]
≈5.1×1018? kg[6]
(6.91 ± 1.93) × 1018[3] kg
Mean density 1.39 ± 0.50[3] g/cm3
Rotation period 4.775 h[1]
Albedo 0.05[1]
Spectral type C[1]
Absolute magnitude (H) 7.24[1]

423 Diotima is a one of the larger main-belt asteroids. It is classified as a C-type asteroid[1] and is probably composed of primitive carbonaceous material.

It was discovered by Auguste Charlois on December 7, 1896, in Nice. In the late 1990s, a network of astronomers worldwide gathered lightcurve data that was ultimately used to derive the spin states and shape models of 10 new asteroids, including 423 Diotima. The light curve for this asteroid varies "a lot" depending on the position, with the brightness variations ranging from almost zero to up to 0.2 in magnitude.[7][8] Dunham (2002) used 15 chords and obtained an estimated size of 171 x 138 km.[2]

Name[edit]

Diotima is named for Diotima of Mantinea, a priestess who was one of Socrates's teachers. It is one of seven of Charlois's discoveries that was expressly named by the Astromomisches Rechen-Institut (Astronomical Calculation Institute).[9]

The name is stressed on the penultimate syllable, /d.əˈtmə/ dy-ə-TY-mə, or as Latin Diotīma.

References[edit]

  1. ^ a b c d e f "JPL Small-Body Database Browser: 423 Diotima (1896 DB)". 2008-09-09 last obs. Retrieved 2008-11-10. 
  2. ^ a b Vasundhara, R; Kuppuswamy, Ramamoorthy, Velu, Venkataramana (2006). "Occultation of 2UCAC 42376428 by (423) Diotima on 2005 March 06". Astronomical Society of India 34: 21–26. Retrieved 2008-11-30. 
  3. ^ a b c Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73: 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009.  See Table 1.
  4. ^ Michalak, G. (2001). "Determination of asteroid masses". Astronomy & Astrophysics 374 (2): 703–711. Bibcode:2001A&A...374..703M. doi:10.1051/0004-6361:20010731. Retrieved 2008-11-10. 
  5. ^ Michalak2001 assumed masses of perturbing asteroids used in calculations of perturbations of the test asteroids.
  6. ^ Using the volume of an ellipsoid of 209x171x138km * an assumed density of 2 g/cm³ yields a mass (m=d*v) of 5.1E+18 kg
  7. ^ Durech, J. et al. (April 2007), "Physical models of ten asteroids from an observers' collaboration network", Astronomy and Astrophysics 465 (1): 331–337, Bibcode:2007A&A...465..331D, doi:10.1051/0004-6361:20066347. 
  8. ^ Durech, J.; Kaasalainen, M.; Marciniak, A.; Allen, W. H. et al. “Asteroid brightness and geometry,” Astronomy and Astrophysics, Volume 465, Issue 1, April I 2007, pp. 331-337.
  9. ^ Schmadel Lutz D. Dictionary of Minor Planet Names (fifth edition), Springer, 2003. ISBN 3-540-00238-3.

External links[edit]