Star Birth in Scorpio - Stellar nursery in Scorpius - RCW 120 is a star-forming...

Star Birth in Scorpio - Stellar nursery in Scorpius - RCW 120 is a star-forming region about 4200 years from Earth in the constellation Scorpio. In the center a hot and massive star emits powerful ultraviolet radiation, which ionize the surrounding gas, tearing off electrons from the hydrogen atoms and producing the characteristic red glow of H - alpha emissions. As this ionized region extends into space, the associated shock wave meets the surrounding cold interstellar gas and cosmic dust. This gas becomes unstable and collapses under its own gravite forming dense, cold clouds or new stars will be born. These very cold clouds (- 250 degres Celsius) can only be detected in submillimetre wavelength; they appear here in blue thanks to the data obtained by the APEX telescope which observes this radiation. Illustrating the power of submillimetre - wavelength astronomy, an APEX image reveals how an expanding bubble of ionised gas about ten light - years across is causing the surrounding material to collapse into dense clumps that are the birthplaces of new stars. The region, called RCW120, is about 4200 light years from Earth, towards the constellation of Scorpius. A hot, massive star in its centre is emitting huge amounts of ultraviolet radiation, which ionises the surrounding gas, stripping the electrons from hydrogen atoms and producing the characteristic red glow of so - called H - alpha emission. Here, the submillimetre emission is shown as the blue clouds surrounding the reddish glow of the ionised gas (shown with data from the SuperCosmoS H - alpha survey). The image also contains data from the Second Generation Digitized Sky Survey (I - band shown in blue, R - band shown in red). As this ionised region expands into space, the associated shock wave sweeps up a layer of the surrounding cold interstellar gas and cosmic dust. This layer b