Saturn’s moon Pandora

What do the craters of Saturn’s small moon Pandora look like up close? To help find out, NASA sent the robotic Cassini spacecraft, now orbiting Saturn, past the unusual moon two weeks ago.

The highest resolution image of Pandora ever taken was then captured from about 40,000 kilometers out and is featured here.

pandora cassini

Structures as small as 300 meters can be discerned on 80-kilometer wide Pandora. Craters on Pandora appear to be covered over by some sort of material, providing a more smooth appearance than sponge-like Hyperion, another small moon of Saturn.

Curious grooves and ridges also appear to cross the surface of the small moon. Pandora is partly interesting because, along with its companion moon Prometheus, it helps shepherd the particles of Saturn’s F ring into a distinct ring.

Image Credit: NASA, JPL-Caltech, Space Science Institute

NGC 6357: Star Forming Region

Star forming region in our galaxy

Pictured above is a star forming region about 5,500 light years from Earth.

  1. NGC 6357 is a region where radiation from young stars is energizing the surrounding gas and dust.
  2. This composite contains X-ray data from Chandra (purple) plus infrared (orange) and optical data (blue).
  3. X-rays can penetrate the shrouds of gas and dust surrounding infant stars like those in NGC 6357.

NGC 6357 is actually a “cluster of clusters,” containing at least three clusters of stars, including many massive, luminous stars. The X-rays from Chandra and ROSAT reveal hundreds of point sources, which are the young stars in NGC 6357, as well as diffuse X-ray emission from hot gas. There are bubbles, or cavities, that have been created by radiation and material blowing away from the surfaces of massive stars, plus supernova explosions.

Astronomers call NGC 6357 and other objects like it “HII” (pronounced “H-two”) regions. An HII region is created when the radiation from hot, young stars strips away the electrons from neutral hydrogen atoms in the surrounding gas to form clouds of ionized hydrogen, which is denoted scientifically as “HII”.

Researchers use Chandra to study NGC 6357 and similar objects because young stars are bright in X-rays. Also, X-rays can penetrate the shrouds of gas and dust surrounding these infant stars, allowing astronomers to see details of star birth that would be otherwise missed.

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Credit: X-ray: NASA/CXC/PSU/L.Townsley et al;

Optical: UKIRT; Infrared: NASA/JPL-Caltech