[meteorite-list] Comet 67P/Churyumov-Gerasimenko is a Contact Binary

[Ron Baalke]

http://www.planetary.org/blogs/emily-lakdawalla/2014/07150633-quick-rosetta-update.html

Quick Rosetta update: Churyumov-Gerasimenko is a contact binary!
Posted by Emily Lakdawalla (Blog)
July 15, 2014

I'm just back from vacation and struggling to catch up but I could not 
wait to post these amazing new images of comet Churymov-Gerasimenko from 
Rosetta. The nucleus of the comet is clearly a contact binary -- two smaller 
(and unequally sized object) in close contact. The CNES page where this 
photo was released says the whole nucleus measures 4 by 3.5 kilometers, 
in good agreement with Hubble and Spitzer estimates. Philippe Lamy is 
quoted as estimating that the two components would have come into contact 
at a relative speed of about 3 meters per second in order to stick together 
in this way.

[Image]
Comet Churyumov-Gerasimenko from Rosetta on July 11, 2014

As Rosetta approached its target comet, the shape of the nucleus was revealed 
to be a contact binary -- two unequal-sized objects in contact with each 
other. All together, the object is about 4 by 3.5 kilometers in size.
Wow, wow, wow. I can't wait to get closer!

This unusual shape could present a navigational challenge for the Philae 
lander team. The CNES release quotes Philae navigator Eric Jurado as saying 
that "navigation around such a body should not be much more complex than 
around a nucleus of irregular spherical type, but landing the Philae probe 
[scheduled for November 11], however, could be more difficult, as this 
form restricts potential landing zones."