511 Davida


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 largest and most-massive asteroids. Davida is named after David Peck Todd, an astronomy professor at Amherst College.

Physical characteristics

It is approximately 270–310 km in diameter and comprises an estimated 1.5% of the total mass of the asteroid belt. It is a C-type asteroid, which means that it is dark in colouring with a 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. show that craters of this size "can be expected from the impactor size distribution, without likelihood of catastrophic disruption of Davida."

Mass

In 2001, Michalak estimated Davida to have a mass of kg. In 2007, Baer and Chesley estimated Davida to have a mass of kg. , Baer suggests Davida has a mass of kg. 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.

Occultations

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