809 Lundia
Asteroid 809 Lundia (apparent magnitude 16.6) near a mag 15.6 star.
|
|
| Discovery | |
|---|---|
| Discovered by | Max Wolf |
| Discovery date | August 11, 1915 |
| Designations | |
|
Named after
|
Lund Observatory |
| 1915 XP; 1936 VC | |
| Main belt | |
| Orbital characteristics | |
| Epoch November 26, 2005 (JD 2453700.5) | |
| Aphelion | 407.368 Gm (2.723 AU) |
| Perihelion | 275.743 Gm (1.843 AU) |
| 341.556 Gm (2.283 AU) | |
| Eccentricity | 0.193 |
| 1260.094 d (3.45 a) | |
|
Average orbital speed
|
19.53 km/s |
| 42.298° | |
| Inclination | 7.143° |
| 154.685° | |
| 196.321° | |
| Physical characteristics | |
| Dimensions | 10.26 ± 0.07[1] km |
| Mass | (9.27 ± 3.09) × 1014[1] kg |
|
Mean density
|
1.64 ± 0.10[1] g/cm3 |
| 0.001–0.003 m/s² (estimate) | |
| 0.003–0.005 km/s (estimate) | |
| Temperature | 165-180 K max: 260-280 K |
|
Spectral type
|
V |
| 11.8 | |
809 Lundia is a small, binary, V-type asteroid[2] 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.[3]
Binary system
Lightcurve observations in 2005 revealed that Lundia is a binary system of two similarly sized objects orbiting their common centre of gravity. "Lundia" now refers to one of the objects, the other being provisionally designated S/2005 (809) 1. 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.[4] Due to the similar size of the primary and secondary the Minor Planet Center lists this as a binary companion.[5]
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,[4] 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
- ↑ 1.0 1.1 1.2 Lua error in package.lua at line 80: module 'strict' not found. See Table 1.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 4.0 4.1 Poznań observatory [1] (Lightcurve showing signature of the binary)
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
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
