Near-Earth asteroid 1994 CC is a triple system

This is a really cool discovery. I wrote last week that upcoming near-Earth asteroid approaches don't seem to be nearly as interesting as some of the close approaches we had in March, but this asteroid that flew by us in June has turned out to be a triple system, which is quite rare and a nice surprise.

Object	Close-Approach Date	Miss Distance Nominal (LD/AU)	V relative (km/s)	N sigma	H (mag)
136617 (1994 CC)	2009-Jun-10	6.6/0.0168	8.39	8.84e+05	17.7

1994 CC has a diameter some 700 metres or so, and these newly discovered moons are 50 m or so each.


The article says that the next comparable flyby for this asteroid won't occur until 2074, but there are quite a few fairly close approaches between now and then. The next one is 21 September 2011 at 0.351 AU:

Then a much closer approach 27 May 2030:

And 14 September 2032:

Those aren't close enough that we would be able to get the same quality photos we did this time from Earth, but good opportunities to send a probe if we ever decided to.

A panel recently recommended sending humans to destinations like asteroids before trying to settle the Moon and Mars, and a binary or trinary system if possible would even be better simply for the attention it would get. Landing on and exploring an asteroid is great; landing on and exploring an asteroid with two moons of its own is mindblowingly awesome.

A page here gives 36 as the number of Earth-crossing asteroids with moons, two of which are trinary systems. Not a bad selection to choose from.