Diffuse nebula NGC 6357 seen by Chandra

NGC 6357 is a diffuse nebula near NGC 6334 in the constellation Scorpius. The nebula contains many proto-stars shielded by dark disks of gas, and young stars wrapped in expanding "cocoons" or expanding gases surrounding these small stars. It is also known as the Lobster Nebula.

The nebula was also given the name War and Peace Nebula by the Midcourse Space Experiment scientists because of its appearance as well as the name "Madokami Nebula" as it resembles one of the main characters, Madoka Kaname from the Japanese anime Puella Magi Madoka Magica.

This composite image contains X-ray data from NASA's Chandra X-ray Observatory and the ROSAT telescope (purple), infrared data from NASA's Spitzer Space Telescope (orange), and optical data from the SuperCosmos Sky Survey (blue) made by the United Kingdom Infrared Telescope.

This diffuse nebula lies about 5,500 light years from Earth and it is actually a "cluster of clusters," containing at least three clusters of young stars, including many hot, 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.

These types of objects are called HII regions by astronomers, regions which are 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".

Chandra's 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. A recent paper on Chandra observations of NGC 6357 by Leisa Townsley of Pennsylvania State University appeared in The Astrophysical Journal Supplement Series and is available online.

Credit: X-ray: NASA/CXC/PSU/L.Townsley et al; Optical: UKIRT; Infrared: NASA/JPL-Caltech, Wikipedia