Astronomy:2002 VE68

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2002 VE68
Discovery
Discovered byLONEOS
Discovery dateNovember 11, 2002
Designations
2002 VE68
Minor planet categoryAten asteroid,[1][2]
Mercury grazer,
Venus crosser,
Earth crosser
Orbital characteristics[2][3][4]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc4730 days (12.95 yr)
|{{{apsis}}}|helion}}1.0205341407 astronomical unit|AU (152.66973443 Gm) (Q)
|{{{apsis}}}|helion}}0.426685951 AU (63.8313097 Gm) (q)
0.7236100459 AU (108.25052208 Gm) (a)
Eccentricity0.41033717 (e)
Orbital period0.62 yr (224.8 d)
Mean anomaly324.184981° (M)
Mean motion1.60120594°/day (n)
Inclination9.00657594° (i)
Longitude of ascending node231.567349° (Ω)
355.446011° (ω)
Earth MOID0.0257506 AU (3.85223 Gm)
Jupiter MOID3.96126 AU (592.596 Gm)
Physical characteristics
Dimensions210–470 m[lower-alpha 1][5]
Rotation period13.50 h (0.563 d)[2]
Absolute magnitude (H)20.5[2]


2002 VE68, also written 2002 VE68, is a temporary quasi-satellite of Venus.[6] It was the first quasi-satellite to be discovered around a major planet in the Solar System. In a frame of reference rotating with Venus, it appears to travel around it during one Venerean year but it actually orbits the Sun, not Venus.[7]

Discovery, orbit and physical properties

It was discovered on November 11, 2002 at Lowell Observatory. As of February 2013, 2002 VE68 has been observed telescopically 457 times with a data-arc span of 2,947 days and it was the target of Doppler observations in 5 occasions; therefore, its orbit is very well determined. Its semi-major axis (0.7237 AU) is very similar to that of Venus but its eccentricity is rather large (0.4104) and its orbital inclination is also significant (9.0060°). The spectrum of 2002 VE68 implies that it is an X-type asteroid and hence an albedo of about 0.25 should be assumed.[8] This combined with an absolute visual magnitude of 20.50 gives a diameter of about 200 m.[8] Its rotational period is 13.5 h and its light curve has an amplitude of 0.9 mag which hints at a very elongated body, perhaps a contact binary.[8]

Quasi-satellite dynamical state and orbital evolution

The existence of retrograde satellites or quasi-satellites was first considered by J. Jackson in 1913[9] but none was discovered until almost 100 years later.[7] 2002 VE68 was the first quasi-satellite to be discovered, in 2002, although it was not immediately recognized as such. 2002 VE68 was identified as a quasi-satellite of Venus by Seppo Mikkola, Ramon Brasser, Paul A. Wiegert and Kimmo Innanen in 2004, two years after the actual discovery of the object.[6][7] From the perspective of a hypothetical observer in a frame of reference rotating with Venus, it appears to travel around the planet during one Venusian year although it does not orbit Venus but the Sun like any other asteroid. As quasi-satellite, this minor body is trapped in a 1:1 mean-motion resonance with Venus. Besides being a Venus co-orbital, this Aten asteroid is also a Mercury grazer and an Earth crosser. 2002 VE68 exhibits resonant (or near-resonant) behavior with Mercury, Venus and Earth.[10][11] It seems to have been co-orbital with Venus for only the last 7,000 years, and is destined to be ejected from this orbital arrangement about 500 years from now.[7] During this time, its distance to Venus has been and will remain larger than about 0.2 AU (3·107 km).

Potentially hazardous asteroid

2002 VE68 is included in the Minor Planet Center list of Potentially Hazardous Asteroids (PHAs) because it comes relatively frequently to within 0.05 AU of Earth. Approaches as close as 0.04 AU occur with a periodicity of 8 years due to its near 8:13 resonance with Earth.[10] 2002 VE68 was discovered during the close approaches of November 11, 2002. During the last close encounter on November 7, 2010, 2002 VE68 approached Earth within 0.035 AU (13.6 Lunar distances), brightening below 15th magnitude. Its next fly-by with Earth will take place on November 4, 2018 at 0.038 AU (5,700,000 km; 3,500,000 mi).[12] Numerical simulations indicate that an actual collision with Earth during the next 10,000 years is not likely, although dangerously close approaches to about 0.002 AU are possible.[10]

See also

Notes

  1. ↑ This is assuming an albedo of 0.25–0.05.

References

  1. ↑ List Of Aten Minor Planets
  2. ↑ 2.0 2.1 2.2 2.3 "2002 VE68". JPL Small-Body Database. Jet Propulsion Laboratory. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2002VE68. 
  3. ↑ AstDys-2 on 2002 VE68 Retrieved 2012-08-13
  4. ↑ NEODyS-2 on 2002 VE68 Retrieved 2012-08-13
  5. ↑ Absolute-magnitude conversion table (H)
  6. ↑ 6.0 6.1 Discovery of the first quasi-satellite of Venus (press announcement, Tuorla Observatory)
  7. ↑ 7.0 7.1 7.2 7.3 Asteroid 2002 VE68, a quasi-satellite of Venus
  8. ↑ 8.0 8.1 8.2 Physical characterization of 2002 VE68, a quasi-moon of Venus
  9. ↑ Retrograde satellite orbits
  10. ↑ 10.0 10.1 10.2 On the dynamical evolution of 2002 VE68
  11. ↑ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl. "Asteroid 2012 XE133, a transient companion to Venus". Monthly Notices of the Royal Astronomical Society 432 (2): 886–893. doi:10.1093/mnras/stt454. Bibcode: 2013MNRAS.432..886D. http://adsabs.harvard.edu/doi/10.1093/mnras/stt454. 
  12. ↑ "JPL Close-Approach Data: (2002 VE68)". http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2002VE68;cad=1#cad. 
Further reading

External links




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