809 Lundia

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809 Lundia
809Lun-LB1-mag17.jpg
Asteroid 809 Lundia (apparent magnitude 16.6) near a mag 15.6 star
Discovery
Discovered by Max Wolf
Discovery date11 August 1915
Designations
(809) Lundia
Pronunciation /ˈlʌndiə/
Named after
 Lund Observatory
1915 XP; 1936 VC
Main belt
Orbital characteristics [1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 100.48 yr (36700 d)
Aphelion 2.72316  AU (407.379  Gm)
Perihelion 1.84193 AU (275.549 Gm)
2.28254 AU (341.463 Gm)
Eccentricity 0.19304
3.45 yr (1259.6 d)
76.7867°
0° 17m 8.912s / day
Inclination 7.14911°
154.580°
196.162°
Physical characteristics
Dimensions 10.26 ± 0.07 km [2]
Mass (9.27 ± 3.09) × 1014 kg [2]
Mean density
1.64 ± 0.10 g/cm3 [2]
15.4142  h (0.64226  d)
V
12.2

    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.

    Contents

    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. The satellite remains undesignated. [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. 1 2 "809 Lundia (1915 XP)". JPL Small-Body Database . NASA/Jet Propulsion Laboratory . Retrieved 4 May 2016.
    2. 1 2 3 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. 1 2 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.
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