29 Amphitrite

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29 Amphitrite 29 Amphitrite symbol.svg
29Amphitrite (Lightcurve Inversion).png
A three-dimensional model of 29 Amphitrite based on its light curve
Discovered by A. Marth
Discovery date March 1, 1854
MPC designation (29) Amphitrite
Pronunciation /ˌæmfɪˈtrt/ am-fi-TRY-tee
Named after
A899 NG
Main belt
Orbital characteristics[1]
Epoch June 14, 2006 (JD 2453900.5)
Aphelion 409.809 Gm (2.739 AU)
Perihelion 354.398 Gm (2.369 AU)
382.103 Gm (2.554 AU)
Eccentricity 0.073
1491.013 d (4.08 a)
18.61 km/s
Inclination 6.096°
Physical characteristics
Dimensions 233×212×193 km[2]
212.2 ± 6.8 km (IRAS)[1]
Mass 1.18×1019 kg[2]
Mean density
2.36 ± 0.26 g/cm³[2]
0.0593 m/s²
0.1122 km/s
0.2246 d (5.390 h)[1][1]
Albedo 0.1793 (geometric[1][2]
Temperature ~170 K
Spectral type
8.65[3] to 11.46
0.21" to 0.078"

29 Amphitrite is one of the largest S-type asteroids, probably third in diameter after Eunomia and Juno, although Iris and Herculina are similar in size.


Amphitrite was discovered by Albert Marth on March 1, 1854, at the private South Villa Observatory, in Regent's Park, London. It was Marth's only asteroid discovery, its name was chosen by George Bishop, the owner of the observatory, who named it after Amphitrite, a sea goddess in Greek mythology.[4]


Amphirite's orbit is less eccentric and inclined than those of its larger cousins; indeed, it is the most circular of any asteroid discovered up to that point. As a consequence, it never becomes as bright as Iris or Hebe, especially as it is much further from the Sun than those asteroids, it can reach magnitudes of around +8.6 at a favorable opposition, but usually is around the binocular limit of +9.5.

In 2007, James Baer and Steven R. Chesley estimated Amphitrite to have a mass of 1.9×1019 kg.[5] A more recent estimate by Baer suggests it has a mass of 1.18×1019 kg.[2]

A satellite of the asteroid is suspected to exist, based on lightcurve data collected by Edward F. Tedesco;[6][7] in 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty.[8]


  1. ^ a b c d e "JPL Small-Body Database Browser: 29 Amphitrite". 2008-04-14 last obs. Retrieved 2008-11-10. 
  2. ^ a b c d Jim Baer (2008). "Recent Asteroid Mass Determinations". Personal Website. Retrieved 2008-11-27. 
  3. ^ "AstDys (29) Amphitrite Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-06-26. 
  4. ^ Lutz D. Schmadel, Dictionary of Minor Planet Names: Addendum to Fifth Edition: 2006 - 2008.
  5. ^ Baer, James; Steven R. Chesley (2008). "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris" (PDF). Celestial Mechanics and Dynamical Astronomy. Springer Science+Business Media B.V. 2007. 100 (2008): 27–42. Bibcode:2008CeMDA.100...27B. doi:10.1007/s10569-007-9103-8. Retrieved 2008-11-10. 
  6. ^ Tedesco, E. F. (March 1979). "Binary Asteroids: Evidence for Their Existence from Lightcurves". Science, New Series. 203 (4383): 905–907. Bibcode:1979Sci...203..905T. doi:10.1126/science.203.4383.905. PMID 17771729. 
  7. ^ van Flandern, T. C.; Tedesco, E. F.; Binzel, R. P. (1979). "Satellites of asteroids". Asteroids. Tucson, AZ: University of Arizona Press. pp. 443–465. 
  8. ^ Gradie, J.; Flynn, L. (March 1988), "A Search for Satellites and Dust Belts Around Asteroids: Negative Results", Abstracts of the Lunar and Planetary Science Conference, 19, pp. 405–406, Bibcode:1988LPI....19..405G. 

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