809 Lundia is a small, binary, V-type asteroid orbiting within the Flora family in the main belt. It is named after Lund Observatory, Sweden.
Characteristics
Lundia orbits within the Flora family. However, its V-type spectrum indicates that it is not genetically related to the Flora family, but rather is probably a fragment (two fragments, if its moon is included) ejected from the surface of 4 Vesta by a large impact in the past. Its orbit lies too far from Vesta for it to actually be a member of the Vesta family. It is not clear how it arrived at an orbit so far from Vesta, but other examples of V-type asteroids orbiting fairly far from their parent body are known. A mechanism of interplay between the Yarkovsky effect and nonlinear secular resonances (primarily involving Jupiter and Saturn) has been proposed.
Binary system
Lightcurve observations in 2005 revealed that Lundia is a binary system of two similarly sized objects orbiting their common centre of gravity. The satellite remains undesignated. The similarity of size between the two components is suspected because during mutual occultations the brightness drops by a similar amount independently of which component is hidden. Due to the similar size of the primary and secondary the Minor Planet Center lists this as a binary companion.
Assuming an albedo similar to 4 Vesta (around 0.4) suggests that the components are about 7 km across. They orbit each other in a period of 15.4 hours, which roughly indicates that the separation between them is very close: to the order of 10–20 km if typical asteroid albedo and density values are assumed.
References
External links
- Electronic Telegram No. 239 announcing the binary system (2005 October 1)
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- (809) Lundia, datasheet, johnstonsarchive.net
- Asteroids with Satellites, Robert Johnston, johnstonsarchive.net
- Lightcurve showing signature of the binary
- 809 Lundia at AstDyS-2, Asteroids—Dynamic Site
- Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
- 809 Lundia at the JPL Small-Body Database
