809 Lundia
Encyclopedia
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
.
The V-type spectrum indicates that it is not genetically related to the Flora family
, but rather is probably a fragment (actually two fragments) ejected off the surface of nearby 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 fairly far from their parent body are known. A mechanism of interplay between the Yarkovsky effect
and nonlinear secular resonance
s (primarily involving Jupiter and Saturn) has been proposed
(around 0.4), suggests that the components are about 7 km across. They orbit each other with a period of 15.4 hours, which roughly indicates that the binary is very close — the separation being of the order of 10–20 km, if typical asteroid albedo and density values are assumed.
Due to the similar size of the primary and secondary the Minor Planet Center
lists this as a binary companion
.
Binary asteroid
A binary asteroid is a system of two asteroids orbiting their common center of mass, in analogy with binary stars. 243 Ida was the first binary asteroid to be identified when the Galileo spacecraft did a flyby in 1993...
, V-type asteroid
V-type asteroid
The spectra of the V-type asteroids or Vestoids are similar to that of 4 Vesta, by far the largest asteroid in this class ....
orbiting within the Flora family
Flora family
The Flora family of asteroids is a large grouping of S-type asteroids in the inner main belt, whose origin and properties are relatively poorly understood at present...
in the Main Belt. It is named after Lund Observatory
Lund Observatory
Lund Observatory is the official English name for the astronomy department at Lund University. As of January 2010 Lund Observatory is part of The department of astronomy and theoretical physics at Lund University...
, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
.
The V-type spectrum indicates that it is not genetically related to the Flora family
Flora family
The Flora family of asteroids is a large grouping of S-type asteroids in the inner main belt, whose origin and properties are relatively poorly understood at present...
, but rather is probably a fragment (actually two fragments) ejected off the surface of nearby 4 Vesta
4 Vesta
Vesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about . It was discovered by Heinrich Wilhelm Olbers on March 29, 1807, and is named after the Roman virgin goddess of home and hearth, 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
Vesta family
The Vesta or Vestian family of asteroids is a large and prominent grouping of mostly V-type asteroids in the inner asteroid belt in the vicinity of 4 Vesta...
It is not clear how it arrived at an orbit so far from Vesta, but other examples of V-type asteroids fairly far from their parent body are known. A mechanism of interplay between the Yarkovsky effect
Yarkovsky effect
The Yarkovsky effect is a force acting on a rotating body in space caused by the anisotropic emission of thermal photons, which carry momentum...
and nonlinear secular resonance
Secular resonance
A secular resonance is a type of orbital resonance.Secular resonances occur when the precession of two orbits is synchronised . A small body in secular resonance with a much larger one will precess at the same rate as the large body...
s (primarily involving Jupiter and Saturn) has been proposed
Binary system
A satellite, designated S/2005 (809) 1, was identified based on lightcurve observations in 2005. In fact, the size of the two components appear to be similar, because during mutual occultations the brightness drops by a similar amount independently of which component is hidden. Assuming an albedo similar to 4 Vesta4 Vesta
Vesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about . It was discovered by Heinrich Wilhelm Olbers on March 29, 1807, and is named after the Roman virgin goddess of home and hearth, Vesta....
(around 0.4), suggests that the components are about 7 km across. They orbit each other with a period of 15.4 hours, which roughly indicates that the binary is very close — the separation being of the order of 10–20 km, if typical asteroid albedo and density values are assumed.
Due to the similar size of the primary and secondary the Minor Planet Center
Minor Planet Center
The Minor Planet Center operates at the Smithsonian Astrophysical Observatory , which is part of the Center for Astrophysics along with the Harvard College Observatory ....
lists this as a binary companion
Binary system (astronomy)
A binary system is an astronomical term referring to two objects in space which are so close that their gravitational interaction causes them to orbit about a common center of mass. Some definitions A binary system is an astronomical term referring to two objects in space (usually stars, but also...
.
External links
- Electronic Telegram No. 239 announcing the binary system (2005 October 1)
- Discovery Circumstances: Numbered Minor Planets
- Johnston Archive entry for 809 Lundia
- Lightcurve showing signature of the binary