809 Lundia

809 Lundia is a small, binary, V-type asteroid[3] 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.[4]

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.[5] Due to the similar size of the primary and secondary the Minor Planet Center lists this as a binary companion.[6]

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,[5] 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. ^ "809 Lundia (1915 XP)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 4 May 2016.
  2. ^ a b c Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73: 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
  3. ^ M. Florczak; D. Lazarro & R. Duffard (2002). "Discovering New V-Type Asteroids in the Vicinity of 4 Vesta". Icarus. 159: 178–182. Bibcode:2002Icar..159..178F. doi:10.1006/icar.2002.6913.
  4. ^ V. Carruba, et al. (2005). "On the V-type asteroids outside the Vesta family". Astronomy & Astrophysics. 441 (2): 819–829. arXiv:astro-ph/0506656. Bibcode:2005A&A...441..819C. doi:10.1051/0004-6361:20053355.
  5. ^ a b Poznań observatory "Physical studies of asteroids at Poznan Observatory". Archived from the original on 2 July 2001. Retrieved 2 July 2001. (Lightcurve showing signature of the binary)
  6. ^ "Satellites and Companions of Minor Planets". IAU / Central Bureau for Astronomical Telegrams. Archived from the original on 21 January 2011. Retrieved 3 July 2011.

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 Edit this at Wikidata
    • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters
Authority control databases Edit this at Wikidata
  • JPL SBDB
  • MPC