511 Davida is a large C-type asteroid in the asteroid belt. It is one of the largest asteroids; approximately tied for 7th place, to within measurement uncertainties, and the 5th or 6th most massive. It was discovered by R. S. Dugan in 1903. Davida is named after David Peck Todd, an astronomy professor at Amherst College.
 | |
| Discovery | |
|---|---|
| Discovered by | R. S. Dugan |
| Discovery date | May 30, 1903 |
| Designations | |
Designation | (511) Davida |
| Pronunciation | /dəˈviːdə/,[1] Latin Dāvīda |
Named after | David Peck Todd |
| 1903 LU | |
| main-belt · (outer) Meliboea [2] | |
| Adjectives | Davidian /dəˈvɪdiən/[3] |
| Orbital characteristics[4] | |
| Epoch July 01, 2021 (JD 2459396.5, heliocentric) | |
| Aphelion | 3.759 AU |
| Perihelion | 2.569 AU |
| 3.163 AU | |
| Eccentricity | 0.188 |
| 5.626 yr (2055 d) | |
| 113° | |
| Inclination | 15.94° |
| 107.6° | |
| 337.2° | |
| Physical characteristics | |
| Dimensions | (357 ± 2) × (294 ± 2) × (231 ± 50) km[6][a] |
| 298±4 km[7] | |
| Flattening | 0.30[b] |
| Mass | (26.6±7.3)×1018 kg[7] (38±2)×1018 kg[c][5] |
Mean density | 1.92±0.53 g/cm3[7] 2.97±1.30 g/cm3[5] |
| 0.2137 d (5.130 h) | |
| Albedo | 0.076±0.007 geometric (0.717±0.013 BV, 0.363±0.020)[4] |
| Temperature | ~160 K |
Spectral type | C |
| 9.50[8] to 12.98 | |
| 6.43[4] | |
Physical characteristics
editDavida is approximately 270–310 km in diameter and comprises an estimated 1.5% of the total mass of the asteroid belt.[9][10][d] It is a C-type asteroid, which means that it is dark in colouring with a carbonaceous chondrite composition.
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
editIn 2001, Michalak estimated Davida to have a mass of (6.64±0.56)×1019 kg.[11][e] In 2007, Baer and Chesley estimated Davida to have a mass of (5.9±0.6)×1019 kg.[12] As of 2010[update], Baer suggests Davida has a mass of (3.84±0.20)×1019 kg.[9] This most recent estimate by Baer indicates that Davida is approximately tied with 704 Interamnia as the fifth-most-massive asteroid, though the error bars of Interamnia are large.[9]
Occultations
editThere have been 9 occultation events observed since 1987, many of which produced two or three chords.[13] Two examples shown here.
Notes
edit- ^ 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).
- ^ Flattening derived from the maximum aspect ratio (c/a): , where (c/a) = 0.70±0.06.[7]
- ^ (18.96 ± 0.99) × 10−12 M☉
- ^ "Baer Mass of 511 Davida" 0.220 / "Mass of Mbelt" 15 = 0.0146
- ^ (3.34±0.28)×10−11 solar masses, per Michalak (2001), extended dynamic model.
References
edit- ^ John Daintith & William Gould, eds. (2006) The Facts On File Dictionary of Astronomy. 5th edition. Infobase Publishing.
- ^ "Asteroid 511 Davida – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved October 24, 2019.
- ^ "Davidian". Merriam-Webster.com Dictionary. Merriam-Webster.
- ^ a b c JPL data Retrieved 2021-09-29
- ^ 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
- ^ Conrad (2007), as cited in Baer et al. (2011).[5]
- ^ a b c d P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
- ^ "Bright Minor Planets 2003". Minor Planet Center. Retrieved May 21, 2008.[permanent dead link]
- ^ a b c Baer, James (2010). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on July 2, 2013. Retrieved February 13, 2011.
- ^ 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.
- ^ 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. Archived from the original on December 4, 2012. Retrieved November 4, 2008.
- ^ Baer, James; Steven R. Chesley (2007). "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris". Celestial Mechanics and Dynamical Astronomy. 100 (2008). Springer Science+Business Media B.V. 2007: 27–42. Bibcode:2008CeMDA.100...27B. doi:10.1007/s10569-007-9103-8.
(2.98±0.30)×10−11 solar masses
- ^ "PDS Asteroid/Dust Subnode". sbn.psi.edu. Archived from the original on April 25, 2018. Retrieved April 27, 2018.
External links
edit- Asteroid occultations, IOTA – International Occultation Timing Association (2011)
- Time lapse photography of Davida
- Al Conrad's research page at Keck
- 511 Davida at AstDyS-2, Asteroids—Dynamic Site
- 511 Davida at the JPL Small-Body Database