- 511 Davida
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511 Davida 
Asteroid 511 Davida imaged by the Keck Observatory, December 2002.DiscoveryDiscovered by R. S. Dugan Discovery date May 30, 1903 DesignationsNamed after David Peck Todd Alternate name(s) 1903 LU Minor planet
categoryMain belt Epoch August 27, 2011 (JD 2455800.5) Aphelion 3.756248648 AU Perihelion 2.57323875 AU Semi-major axis 3.164743701 AU Eccentricity 0.18690453 Orbital period 5.63009883 a (2056.393597 d) Average orbital speed 16.59 km/s Mean anomaly 202.86548° Inclination 15.942247° Longitude of ascending node 107.63617° Argument of perihelion 338.17810° Physical characteristicsDimensions 289±21 km (357±2 × 294±2 × 231±50)[2] Mass 3.84±0.20×1019 kg[3] Mean density 3.45 ± 1.51 g/cm³[3] Rotation period 0.2137235 d (5.13 h) Albedo 0.054–0.066 2 Temperature ~160 K Spectral type C Apparent magnitude 9.50[4] to 12.98 Absolute magnitude (H) 6.22 511 Davida (
/dəˈviːdə/ də-vee-də) is a large main-belt C-type asteroid. It was discovered by R. S. Dugan in 1903. It is one of the ten most massive asteroids. It is approximately 270–310 km in diameter and comprises an estimated 1.5% of the total mass of the asteroid belt.[3][5][6] It is a C-type asteroid, which means that it is dark in colouring with a carbonate composition.Davida is one of the few main-belt asteroids whose shape has been determined by ground-based visual observation. From 2002 to 2007, astronomers at the Keck Observatory used the Keck II telescope, which is fitted with adaptive optics, to photograph Davida. The asteroid is not a dwarf planet: there are at least two promontories and at least one flat facet with 15-km deviations from a best-fit ellipsoid. The facet is presumably a 150-km global-scale crater like the ones seen on 253 Mathilde. Conrad et al. (2007) show that craters of this size "can be expected from the impactor size distribution, without likelihood of catastrophic disruption of Davida."
Davida is named after David Peck Todd, an astronomy professor at Amherst College.
Mass
In 2001, Michalak estimated Davida to have a mass of (6.64±0.56)×1019 kg[7][8] In 2007, Baer and Chesley estimated Davida to have a mass of (5.9±0.6)×1019 kg.[9] As of 2010[update], Baer suggests Davida has a mass of (3.84±0.20)×1019 kg.[3] This most recent estimate by Baer suggests that Davida is less massive than 704 Interamnia, making Davida the sixth-most-massive asteroid, though the error bars overlap.[3]
References
- ^ JPL data Retrieved 2011-09-02
- ^ Conrad (2007). Measurements of the short axis are less precise than the other two, but also involve a discrepancy between fitting the convolved and deconvolved images (241±40 km), and fitting the edges (191±114 km).
- ^ a b c d e Baer, James (2010). "Recent Asteroid Mass Determinations". Personal Website. http://home.earthlink.net/~jimbaer1/astmass.txt. Retrieved 2011-02-13.
- ^ "Bright Minor Planets 2003". Minor Planet Center. http://www.cfa.harvard.edu/iau/Ephemerides/Bright/2003. Retrieved 2008-05-21.
- ^ Pitjeva, E. V. (2005). "High-Precision Ephemerides of Planets—EPM and Determination of Some Astronomical Constants" (PDF). Solar System Research 39 (3): 176. Bibcode 2005SoSyR..39..176P. doi:10.1007/s11208-005-0033-2. http://iau-comm4.jpl.nasa.gov/EPM2004.pdf.
- ^ "Baer Mass of 511 Davida" 0.220 / "Mass of Mbelt" 15 = 0.0146
- ^ Michalak, G. (2001). "Determination of asteroid masses (6) Hebe, (10) Hygiea, (15) Eunomia, (52) Europa, (88) Thisbe, (444) Gyptis, (511) Davida and (704) Interamnia". Astronomy & Astrophysics 374: 703–711. Bibcode 2001A&A...374..703M. doi:10.1051/0004-6361:20010731. http://www.aanda.org/index.php?option=article&access=standard&Itemid=129&url=/articles/aa/abs/2001/29/aa10228/aa10228.html. Retrieved 2008-11-04.
- ^ (3.34±0.28)×10−11 solar masses, per Michalak (2001), extended dynamic model.
- ^ Baer, James; Steven R. Chesley (2007). "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. http://www.springerlink.com/content/h747307j43863228/fulltext.pdf. Retrieved 2008-11-15.: = (2.98±0.30)×10−11*solar masses
- A.R. Conrad et al. (2007). "Direct measurement of the size, shape, and pole of 511 Davida with Keck AO in a single night", Icarus, doi:10.1016/j.icarus.2007.05.004
External links
- Time lapse photography of Davida
- Al Conrad's research page at Keck
- Orbital simulation from JPL (Java) / Horizons Ephemeris
Minor planets navigator Small Solar System bodies Minor planets - Designation
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Comets Meteoroids Lists / categories - Asteroid groups and families
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Categories:- Main Belt asteroids
- C-type asteroids
- Asteroids named for people
- 1903 in science
- Astronomical objects discovered in 1903
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