809 Lundia

Minor Planet
name=809 Lundia
discoverer=Max Wolf
discovery_date=August 11, 1915
designations=1915 XP; 1936 VC
category=Main belt
epoch=November 26, 2005 (JD 2453700.5)
semimajor=341.556 Gm (2.283 AU)
perihelion=275.743 Gm (1.843 AU)
aphelion=407.368 Gm (2.723 AU)
eccentricity=0.193
period=1260.094 d (3.45 a)
inclination=7.143°
asc_node=154.685°
arg_peri=196.321°
mean_anomaly=42.298°
speed=19.53 km/s
dimensions=7–10 km "(estimate)" (for each component)
mass=0.2–2×10¹⁵ each "(estimate)"
density="unknown"
gravity=0.001–0.003 m/s² "(estimate)"
escape_velocity=0.003–0.005 km/s "(estimate)"
rotation="unknown"
spectral_class=V
abs_mag=11.8
albedo="unknown"
temperature=165-180 K
"max:" 260-280 K

809 Lundia is a small, binary, V-type asteroidcite journal | author= M. Florczak, D. Lazarro, & R. Duffard| title= "Discovering New V-Type Asteroids in the Vicinity of 4 Vesta"| journal= Icarus| year= 2002| volume= 159| pages= 178| doi= 10.1006/icar.2002.6913] 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 resonances (primarily involving Jupiter and Saturn) has been proposed [cite journal | author= V. Carruba et al| title= "On the V-type asteroids outside the Vesta family"| journal= Astronomy & Astrophysics| year= 2005| volume= 441| pages= 819| doi= 10.1051/0004-6361:20053355]

Binary

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 Poznań observatory [http://www.astro.amu.edu.pl/Science/Asteroids/] (Lightcurve showing signature of the binary)] . Assuming an albedo similar to 4 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.

References

External links

* [http://cfa-www.harvard.edu/iau/lists/NumberedMPs.txt Discovery Circumstances: Numbered Minor Planets]
* [http://www.johnstonsarchive.net/astro/astmoons/am-00809.html Johnston Archive entry for 809 Lundia]
* [http://www.astro.amu.edu.pl/Science/Asteroids/ Lightcurve showing signature of the binary]