Monday, July 11, 2005

New Rhea Image: Diversity of Impacts


CICLOPS has released this processed view of Rhea's leading hemisphere taken on June 2 from a distance of 1.8 million km (for a resolution of 11 km/pixel, though this view has been magnified 2x to improve feature visibility). This image shows a range of impact phenomena on the surface of Rhea. On the right side of the disk, we can see the now famous ray crater as well as many as two large impact basins near the terminator. The northern impact basin is Tirawa which was measured using this image as being 360 km across (+/- 20 km). There is a second impact basin south of Tirawa more in the shadows, which is at least as large as Tirawa

Phil mentioned a third impact basin 1 basin width south of the southern basin. Maybe Phil can correct me here but I think he is talking about the circular ring seen here near the terminator 1 basin width south of the "southern" basin.

2 Comments:

Anonymous Phil Stooke said...

Yes, it is... I knew this image was coming up. And we should see the basin better in future. This is an interesting image: Tirawa is close enough to the terminator that we can see it has a large central bulge. The 'new' basin, if it is one, looks like a circular trough here, probably because it also has a large central bulge. This is presumably due to relaxation, and it's going to tell us something about the rheology of the interior. There is an as yet unheralded (except by me) somewhat smaller basin northwest of Ithaca Chasma on Tethys which also has this morphology. (I showed it at LPSC, and a couple of big impact specialists who shall remain nameless looked at it but decided it wasn't real, so I'm hoping it will also show up clearly later on...)

Phil

7/11/2005 11:23:00 AM  
Anonymous Gsnorgathon said...

Oh dear. I have to ask, but you might not be able to answer, Phil: is the name of one of them perhaps vaguely Scottish?

7/12/2005 07:46:00 PM  

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