Star forming region in our galaxy
Pictured above is a star forming region about 5,500 light years from Earth.
- NGC 6357 is a region where radiation from young stars is energizing the surrounding gas and dust.
- This composite contains X-ray data from Chandra (purple) plus infrared (orange) and optical data (blue).
- 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