Seeking vulcanoids, finding two small bodies

[Cross-posted and edited from Kentucky Space] Offering a description of the search for "vulcanoids," the hypothesized asteroids near our star, The Planetary Society's Emily Lakdawalla published this image inside the solar orbit of Venus by the extreme explorer, MESSENGER.

More on the pic in a second.

Will vulcanoids ever be found?

No vulcanoids have yet been discovered, and it is not known if any exist. But should they be found, these small, rocky asteroids may yield insights into the formation and early evolution of the solar system. They might contain material left over from the earliest period of planet formation and help determine the conditions under which the terrestrial planets, particularly Mercury, formed....

If they do exist, the vulcanoids would be difficult to spot. First, they would be very small – less than 60 kilometers (37 miles) in diameter (a limit set by Earth-based observations) – and their reflected light would generally be drowned out by the bright glare of the nearby Sun. Because of their proximity to the Sun, searches for vulcanoids from the ground can be carried out only during twilight or or dawn or during solar eclipses.

Having made pulse-pounding flybys of the planet - check out this pic - MESSENGER will take up permanent residence in orbit around Mercury on March 18, 2011.

Those two brighter dots in the lower left side of the image? That's Earth and our moon.


Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington