Our Best Ever Look at Pan, Saturn’s Little “UFO”
Posted by Jason Major
Behold the almighty Pan! Thanks to Cassini’s ring-grazing orbits we’ve just received the highest-resolution images ever of Pan—which, at only about 17 miles (27 km) across admittedly isn’t very “almighty” but its flying saucer-like shape is really quite fascinating!
The raw images above were acquired by Cassini on March 7, 2017 and received on Earth on March 8. I assembled them into an animation to show some of the 3D shape of the little shepherd moon, which orbits Saturn inside the 200 mile wide Encke Gap in the A ring.
Another image highlights the irregular moon’s flying saucer (or ravioli?) shape, due to the wide ridge running around its equator. Pan’s ridge is a buildup of icy material from the rings, which it has collected around its equator over the millennia.
And this image shows Pan within the Encke Gap, which it
keeps clear shares with a ringlet in a horseshoe orbit.
The animation below, captured by Cassini in 2006, shows Pan within the gap but seen from a viewpoint outside and along the ringplane. The difference in thickness between the moon and the rings is very evident here!
Pan was discovered by astronomer Mark Showalter in 1990 using images taken by Voyager 2 in August 1981. It wasn’t until Cassini arrived in 2004 that Pan’s true UFO-like shape—along with its similarly-sized neighbor Atlas—was seen.
Pan orbits Saturn once every 13.8 hours.
Update: Here’s a color version of Pan I made with images acquired in IR, green, and UV color channels on March 7. The colors aren’t accurate to what our eyes would see, but it does show the variation across the ridge and main surface of Pan.