Thursday, July 21, 2005

Raw Images of the Day

New Helene Image: Helene from Afar

CICLOPS' daily release today is this processed view of Saturn's moon Helene. Helene is another small trojan moon, like yesterday's daily release Telesto, but instead of being a trojan of Tethys, Helene is a trojan moon of Dione. Helene orbits at the same distance from Saturn as Dione, but 60 degrees ahead in the orbit, at the L4 Lagrange Point. This image has still too low of resolution to show surface features, but the overall shape of the moon can be seen. This image has a resolution of 5 km/pixel but has been magnified by three times to aid visibility.

Wednesday, July 20, 2005

Press Release: MIT-Williams team catches rare light show with Charon

A group of astronomers from MIT are reporting the successful acquition of data during a stellar occulatation by Pluto's moon Charon on the night of July 10-11. The data was taken using four different telescopes in Chile, as well as one in Brazil. The data from occultation should help to constrain the size of Charon, as well determine if the satellite has an atmosphere.

More information can be found on the MIT website.

T7 flyby altitude raised

I haven't mentioned this before on this page, but last week's Cassini Significant events update reported that the altitude of the T7 flyby, set to take place on September 7, has been raised from 1025 km to 1075 km, based on the recommendation of the Titan Atmospheric Modeling Working Group. There is concern that the haze layer over the summer hemisphere may be inflated compared to the winter hemisphere. All close approaches of Titan thus far have been over the northern hemisphere, the current winter hemisphere. The Cassini data that has gone into the atmospheric model has thus been mostly from the northern hemisphere. So to prevent a safing event caused by a loss in attitude control, the flyby altitude has been raised. Such an increase could lead to issues with mosaic and swath designs for ISS, VIMS, and RADAR as they make observations during the flyby.

New Scientist: Bizarre boulders litter Saturn moon's icy surface

New Scientist has an article now posted regarding the highest resolution ISS image of Enceladus. Some interesting comments, though one needs to very careful about making assumptions that this kind of surface is common on Enceladus until you see where the frame is on the surface, for context. And in terms of making interpretations this early, I think Zibi Turtle said it best:
But Elizabeth Turtle, a Cassini imaging team member at the University of Arizona in Tucson, US, warns there will be no quick answers. “Trying to figure out what is going on is going to take a lot longer than a weekend of swapped emails,” she says.
My bloated inbox certainly understands...not that I am complaining :D

New Telesto Image: Trojan Telesto

CICLOPS has released this highest resolution view of the Tethys trojan Telesto. This moon, only 24 kilometers across, has not yet been seen at high enough resolution to resolve surface features, but images such as this one do allow for the beginning of shape modeling. Higher resolution images should come later this year during encounters that bring Cassini within 20,000 km of this moon.

New Cassini Image: F Ring Shepherds

This view of the F-ring was released by CICLOPS on Monday. This image shows both F-ring shepherds, Pandora on the left and Prometheus on the right, in the same view. While this view has too low of resolution, the serealistic view highlights their relationship to the F-ring.

Sunday, July 17, 2005

Enceladus thoughts and more

Just giving everyone a heads up: I will be out of town starting tonight and will be in Flagstaff for a Titan Surfaces Meeting until Tuesday evening. While I am at it, yes Dad, I got the package. Thanks for the cookies! Anyways, my connection to the internet maybe spotty so don't expect too many updates here over the next couple of days.

On to Enceladus. This little moon continues to amaze. The views of this moon's south polar region were spectacular, including one very high resolution shot taken from a distance of only a few hundred km. Immediately one thinks of Europa, but one has to be careful comparing two very differently sized worlds. I can't count out the possibility of a liquid ocean, but the small size of Enceladus and the prevalence of cratered terrain makes me think that is not what we are see here. I think a more apt analogy is Miranda, with its own dichonomy between concentric ridged corona and heavily cratered terrain. In the case of Miranda, it is thought that upwellings of warm ice produced the coronae. A similar formation mechanism could be invisioned for Enceladus.