Asteroid moon: moonsteroid!

The asteroid 1998 QE2 and its tiny moon visible as a brighter spot below the larger gray blur that’s the asteroid. [Credit: NASA/JPL-Caltech/GSSR]

Today, a relatively large asteroid known as 1998 QE2 will pass Earth, beyond the orbit of the Moon. Yes, it’s named for the cruise ship, but it’s much bigger — 2.7 kilometers along its greatest axis — and correspondingly much more massive. (As I said, the asteroid won’t come even as close as the Moon, so even though 1998 QE2 would be pretty devastating if it hit us, we’re in absolutely no danger.) If you have a telescope and you want more information on how to see the asteroid for yourself, check out David Dickinson’s guide at Universe Today.

The exciting thing for me is the discovery of a small moon orbiting the asteroid. Radar data showed a small body moving around the larger asteroid, which in the video below and image shows up as a bright spot. (Based on the fact that 1998 QE2 is named for a ship named for Queen Elizabeth, I’m tempted to make a Prince Charles/dinghy joke, but I’ll spare you.) This isn’t the first asteroid moon ever seen, but it’s still very cool — not least since it will eventually let astronomers estimate the mass of 1998 QE2. That mass will in turn give some information about the density and composition of the asteroid. The higher-resolution radar maps to come should also reveal more about the moon itself. Stay tuned!

2 Responses to “Asteroid moon: moonsteroid!”

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1 Loren Riley June 1, 2013 at 05:21

I wonder if the IAU would allow the discoverers of the moon to ever actually name it something like ‘Moonsteroid’. Because that would be pretty awesome…
- 2 Matthew R. Francis June 1, 2013 at 08:28
  
  More than 10% of asteroids have moons, so “moonsteroid” wouldn’t be the first choice of names for any particular example of one.

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