As Cassini celebrates 10 years at Saturn, we're beginning to see its long-term observations of Saturnian moons bear fruit. A surprising new result: While Prometheus exerts control over the F ring and Atlas, Pandora -- long thought to be a shepherd of the F ring -- does not.
Cassini flew past Phoebe on June 11, 2004, on its way to entering Saturn orbit. The flyby was almost perfect but overexposure of some images have prevented color mosaics from being produced. Even though Phoebe's body is gray and dull in color, the absence of color images always provoked me. By using VIMS data, I have now produced color mosaics.
It took months of work (and no wonder) but the wait was worth it: here is Cassini's spectacular view of Saturn, captured on July 19, 2013, as Cassini passed through Saturn's shadow. If you're a little confused by the image, I'm here to help: I've posted a video explainer.
In which I summarize Joe Veverka's Kuiper Prize talk at the Division for Planetary Sciences meeting: "Small is NOT Dull: Unravelling the Complexity of Surface Processes on Asteroids, Comets and Small Satellites."
Pluto's moons, formerly known as "P4" and "P5," are now named Kerberos and Styx; I thought I'd help place them into context with a little help from Cassini. Also, Neptune now has a 14th known moon.
I've been out of town for a couple of days and am overwhelmed with work and an overflowing email box. So what do I do about that? I ignore what I'm supposed to be doing and play with Cassini raw image data, of course. Here is a "mutual event" of Mimas (the bigger moon) and Pandora (the outer shepherd of the F ring).
A summary of just one talk from the Division for Planetary Sciences meeting, by Lindy Elkins-Tanton, which provided a neat explanation for how asteroids can be melted and layered on the inside yet have a primitive-looking exterior.
In the first full day of the annual meeting of the Division of Planetary Sciences of the American Astronomical Society, I listened to scientific sessions on icy worlds and on an exoplanet in a four-star system.
Cassini obtained its first high-resolution images of Methone on May 20, 2012. Methone is one of the smallest regular moons of Saturn, having a diameter of only about 3 kilometers. It was the first moon that Cassini discovered, very early in Cassini's mission at Saturn, in 2004.
I enthused about these Helene images the first time they came down from Cassini, and then forgot about them, and then was thrilled anew a couple of weeks ago when Daniel Macháček posted his version, processed from data published by the Cassini imaging team on April 1.
Posted by Emily Lakdawalla on 2012/04/04 12:15 CDT
In the last few days as it's rounded periapsis in its current orbit of Saturn, Cassini has taken a lot of great photos of Saturn's moons. One series of photos was taken from pretty close to Janus, a moon about a third the diameter of Enceladus that orbits between the F and G rings. And among those, several were taken with the moon sitting in front of Saturn.
Posted by Emily Lakdawalla on 2012/01/09 11:23 CST
A recent view from Cassini of Saturn with its largest moon (Titan) and one of its small ringmoons, Prometheus.
Posted by Emily Lakdawalla on 2011/12/22 11:52 CST
Cassini flew close by Dione on December 12 and, as usual, the close pass provided opportunities for lots of dramatic photos, not just of Dione, but of other moons wandering by in the background.
Posted by Emily Lakdawalla on 2011/12/15 11:18 CST
A summary of a new article by Matt Tiscareno about planetary ring systems that reviews the known ring systems of the four giant planets and the prospects for ring systems yet to be discovered.
Posted by Emily Lakdawalla on 2011/09/28 12:28 CDT
Since Cassini currently orbits Saturn within the plane of Saturn's rings, it has lots of chances to catch two or more moons in the same photo. One such "mutual event" happened on September 17, featuring four moons: Titan, Dione, Pan, and Pandora.
Posted by Emily Lakdawalla on 2011/09/15 02:18 CDT
I'm preparing a talk for the Pacific Astronomy and Telescope Show here in Pasadena on Sunday afternoon at 1:45. I have spent the morning putting together a slide that I have long wanted to have for presentations.
Posted by Emily Lakdawalla on 2011/08/26 05:43 CDT
Yesterday Cassini passed unusually close by Hyperion, the oddly shaped moon that orbits Saturn just beyond Titan. Among the many cool images captured during this flyby were three that I used to make this neato view of Hyperion's crescent.