Webb unveils young stars across every stage of formation in Orion's Molecular Clouds
For this NASA/ESA/CSA James Webb Space Telescope Picture of the Month we return to the constellation Orion (the Hunter), a location familiar to Webb. This area of the sky is replete with star-forming clouds that make up a complex hundreds of light-years across. We find ourselves in the giant molecular cloud Orion A, of which the familiar Orion Nebula (also known as M42) is just a part; Webb has taken both close-up and wide-angle looks at M42 before.
The target of these observations, however, requires us to look behind the Orion Nebula. Behind the stars, gas and dust of M42 is a long, massive filament of cold gas and dust called (somewhat confusingly) the Orion Molecular Clouds, which is divided into four parts, OMC-1 through OMC-4. OMC-1 sits immediately behind M42, to the north are OMC-2 and OMC-3, and OMC-4 lies to the south.
This image shows just a small, northern portion of OMC-2, located 1280 light-years from Earth and a little north of the Orion Nebula. Every stage of star formation – from the youngest stellar embryos, to protoplanetary discs, to newly-minted pre-main sequence stars – is contained within just this scene, which stretches 150 light-years across. The intense star-forming activity has produced an impressive display of billowing outflows and sparkling stars atop swirling layers of gas and dark, obscuring clouds.
Molecular clouds such as OMC-2 are vast clumps of gas much more dense than the rest of interstellar space. This density allows complex molecules to form, protected from the radiation given off by other stars, and it means that gravity can cause the cloud to collapse and form stars. The earliest stage of this process is a protostar – a growing star that is being fed gas from the surrounding cloud through a spinning disc of gas. As gas falls onto the protostar, it heats up, powering the glow of the protostar. The immense amount of energy acquired during this process is unleashed in fierce jets of gas from the poles of the star, frequently seen as twin glowing outflows that mark the location of a protostar.
