511 Davida

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511 Davida (də-VEE-də) is a large main belt C-type asteroid. It was discovered by R. S. Dugan in 1903. It is thought to be the sixth most massive asteroid after Ceres, Vesta, Pallas, Hygiea, and Interamnia. It is approximately 270–310 km in diameter and comprises a guestimated 0.5% of the total mass of the asteroid belt. 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.

External links

• Time lapse photography of Davida
• Al Conrad's research page at Keck

References

• 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

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Last updated on Friday March 07, 2008 at 18:13:59 PST (GMT -0800)
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