NASA | MSFC | SAO | Chandra X-ray Observatory | 2017 Jul 12
[c][imghover=http://chandra.harvard.edu/photo/2017/w51/w51_525.jpg]http://chandra.harvard.edu/photo/2017/w ... er_525.jpg[/imghover]X-ray: NASA/CXC/PSU/L.Townsley et al; Infrared: NASA/JPL-Caltech[/c][hr][/hr]In the context of space, the term 'cloud' can mean something rather different from the fluffy white collections of water in the sky or a way to store data or process information. Giant molecular clouds are vast cosmic objects, composed primarily of hydrogen molecules and helium atoms, where new stars and planets are born. These clouds can contain more mass than a million suns, and stretch across hundreds of light years.
The giant molecular cloud known as W51 is one of the closest to Earth at a distance of about 17,000 light years. Because of its relative proximity, W51 provides astronomers with an excellent opportunity to study how stars are forming in our Milky Way galaxy.
A new composite image of W51 shows the high-energy output from this stellar nursery, where X-rays from Chandra are colored blue. In about 20 hours of Chandra exposure time, over 600 young stars were detected as point-like X-ray sources, and diffuse X-ray emission from interstellar gas with a temperature of a million degrees or more was also observed. Infrared light observed with NASA's Spitzer Space Telescope appears orange and yellow-green and shows cool gas and stars surrounded by disks of cool material.
W51 contains multiple clusters of young stars. The Chandra data show that the X-ray sources in the field are found in small clumps, with a clear concentration of more than 100 sources in the central cluster, called G49.5−0.4 ...
The Massive Star-forming Regions Omnibus X-ray Catalog - Leisa K. Townsley et al
- Astrophysical Journal Supplement 213(1):1 (2014 July) DOI: 10.1088/0067-0049/213/1/1
arXiv.org > astro-ph > arXiv:1403.2576 > 11 Mar 2014
See also: http://asterisk.apod.com/viewtopic.php?t=36653