511 Davida

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511 Davida
511 Davida Lightcurve Inversion.png
3D model of Davida based on lightcurve modeling
Discovery
Discovered by R. S. Dugan
Discovery date May 30, 1903
Designations
MPC designation (511) Davida
Pronunciation /dəˈvdə/[2] or /ˈdævɪdə/[3]
Named after
David Peck Todd
1903 LU
main-belt · (outer)
Meliboea[1]
Orbital characteristics[4]
Epoch August 27, 2011 (JD 2455800.5)
Aphelion 3.756248648 AU
Perihelion 2.57323875 AU
3.164743701 AU
Eccentricity 0.18690453
5.63009883 yr (2056.393597 d)
202.86548°
Inclination 15.942247°
107.63617°
338.17810°
Physical characteristics
Dimensions 357 km × 294 km × 231 km[5]
Mean diameter
289±21 km[5]
Mass 3.84±0.20×1019 kg[6]
Mean density
2.97±1.30 g/cm³[6]
0.2137235 d (5.13 h)
Albedo 0.054–0.066 2
Temperature ~160 K
Spectral type
C
9.50[7] to 12.98
6.22

511 Davida is a large C-type asteroid in the asteroid belt. It was discovered by R. S. Dugan in 1903. It is one of the ten most-massive asteroids, and the 7th-largest asteroid. Davida is named after David Peck Todd, an astronomy professor at Amherst College.

Description[edit]

Asteroid 511 Davida (lower left at mag 12.5) near galaxy NGC 5792

It is approximately 270–310 km in diameter and comprises an estimated 1.5% of the total mass of the asteroid belt.[6][8][9] It is a C-type asteroid, which means that it is dark in colouring with a carbonaceous chondrite 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."

Mass[edit]

In 2001, Michalak estimated Davida to have a mass of (6.64±0.56)×1019 kg[10][11] In 2007, Baer and Chesley estimated Davida to have a mass of (5.9±0.6)×1019 kg.[12] As of 2010, Baer suggests Davida has a mass of (3.84±0.20)×1019 kg.[6] 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.[6]

Occultations[edit]

There have been 9 occultation events observed since 1987, many of which produced two or three chords.[13] Two examples shown here.

Occultations by 511 Davida: Left: Double chord occultation of TYC 5597-01223 on 5 August 2016, observed by two amateur astronomers in eastern Australia. Both observers noted step events, thereby detecting the star has two components. Right: Triple chord occultation of TYC 1964-00787, observed on 6 February 2009 by three astronomers in eastern United States.
511 Davida occulted TYC 5597-01223 on 5 August 2016. Two observers recorded the event and both observed step events. Shown here is the step recording by Dave Herald.

References[edit]

  1. ^ "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 2 September 2017. 
  2. ^ from Latin Dāvīda
  3. ^ də-VY-də or DAV-i-də
  4. ^ JPL data Retrieved 2011-09-02
  5. ^ a b 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).
  6. ^ a b c d e Baer, James (2010). "Recent Asteroid Mass Determinations". Personal Website. Retrieved 2011-02-13. 
  7. ^ "Bright Minor Planets 2003". Minor Planet Center. Retrieved 2008-05-21. 
  8. ^ 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. Archived from the original (PDF) on October 31, 2008. 
  9. ^ "Baer Mass of 511 Davida" 0.220 / "Mass of Mbelt" 15 = 0.0146
  10. ^ 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. Retrieved 2008-11-04. [permanent dead link]
  11. ^ (3.34±0.28)×10−11 solar masses, per Michalak (2001), extended dynamic model.
  12. ^ 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. Retrieved 2008-11-15. (2.98±0.30)×10−11 solar masses 
  13. ^ "PDS Asteroid/Dust Subnode". sbn.psi.edu. Archived from the original on April 25, 2018. Retrieved April 27, 2018. 

External links[edit]