October 19, 2017

11.12.10: The “Quasi-Moon” of Venus.

The curious orbit of 2002 VE68. (Created with JPL’s Ephemeris Generator).

   Up until about the mid-19th century, astronomers reported spurious sightings of a moon near our sister world, Venus. These sightings were copious enough to even warrant a name, Neith. Today, most of these observations have gone the way of the Vulcan’s and second Moon of Earth sightings as curiosities, chalked up to background stars or internal reflections in antique optics. Venus has no moon… but an interesting asteroid may vie for the next closest thing.

In 2002, astronomers at the Lowell observatory discovered a curious asteroid in a 225 day orbit about the inner solar system. If that number sounds familiar, that’s because it is; asteroid 2002 VE68 has an orbit that is in a 1:1 lock step resonance with the planet Venus. Astronomers estimate that this resonance was set up about 7,000 years ago during a close encounter with the Earth, and that 2002 VE68 will stay in this resonance for at least another 500 years. Recently, NASA/JPL astronomer Michael Hicks and his team took advantage of a favorable apparition of 2002 VE68 near Earth to obtain photometric measurements of the asteroid with JPL’s table Mountain 0.6 meter telescope. Their measurements suggest that 2002 VE68 is of the E-type asteroid variety, similar to asteroid 2867 Steins photographed by ESA’s Rosetta spacecraft in 2008.

Could 2002 VE68 have been a Neith imposter? The short answer is no; even at its closest approach to Earth, it shines at only +14th magnitude. 2002 VE68 is classified as a Potentially Hazardous Asteroid (PHA), but due to its inclination, it isn’t a threat to Earth any time in the near future. Plus, at its closest approach to Earth, 2002 VE68 would appear nowhere near Venus. Its looping orbit as an Aten-class asteroid takes it inside the orbit of Mercury and just beyond Earth with an aphelion of 1.0207 AU. Viewing from the surface (or cloud tops!) of Venus, 2002 VE68 would appear to make one revolution about the planet once every Venusian year. 2002 VE68 is estimated to be about 250-500 meters in diameter. Only three other quasi-satellites are known in the solar system; two in resonance with the Earth and one future resonator for Mars.

…And what did those astronomers of yore see? More on that next month!

Note: In other Venusian news, the Japanese Space Agencies’ Akatsuki spacecraft failed to enter Venusian orbit; it is now on a heliocentric path about the Sun that will see its free return to Venus in…2017!   

 

Trackbacks

  1. [...] Ideas for a tiny second moon around Earth, dubbed “Lilith,” go all the way back to alleged sightings in the 19th century. “Petit’s Moon” created a temporary sensation in 1846, until it too proved to be spurious. In modern times, spent boosters from the Chinese Chang’e-2 and Apollo 12 lunar missions were tenoriarilidentified as “asteroids” 2010 QW1 and J002E3. Other objects, such as 3753 Cruithne occupy strange horseshoe-shaped orbits around Earth. Venus also has its own suite of TCOs, such as 2002 VE68. [...]

  2. [...] Ideas for a tiny second moon about Earth, dubbed “Lilith,” go every one of the method spine to alleged sightings in the 19th century. “Petit’s Moon” developed a temporary sensation in 1846, until it Also proved to be spurious. In modern times, invested boosters from the Chinese Chang’e-2 and Apollo 12 lunar missions were tenoriarilidentified as “asteroids” 2010 QW1 and J002E3. Various other objects, such as 3753 Cruithne occupy strange horseshoe-shaped orbits about Earth. Venus additionally has actually its own suite of TCOs, such as 2002 VE68. [...]

Speak Your Mind

*