Planck reveals complexity
of star formation
DR EMILY BALDWIN
Posted: 27 April 2010
New images from ESA's Planck space observatory reveal the complex driving forces behind star formation, giving astronomers new insight into the processes that sculpt the dust and gas of our Galaxy.An active star-formation region in the Orion Nebula, showing also the Horsehead Nebula and Barnard's Loop. This image covers a region of 13x13 degrees. It is a three-colour combination constructed from three of Planck's nine frequency channels: 30, 353 and 857 GHz. Image: ESA/LFI & HFI Consortia.
The Planck observatory was launched nearly a year ago and with its microwave vision it can penetrate through the shrouds of dust that optical telescopes are blinded by to reveal intricate glowing structures of star-forming gas and dust.
One of Planck's latest study regions is the well-known Orion Nebula, standing out in the first image (above) as the glowing bright spot at the lower centre. The glowing red region above and to the right of that is the Horsehead Nebula, and the giant red arc is known as Barnard’s Loop, a suspected blast wave from a star that expired inside the region around two million years ago but has left its mark as a 300 light-year diameter bubble rippling through the stellar neighbourhood. The second image (below) details the Perseus region, a slightly calmer region of star-formation, compared with Orion.A low activity, star-formation region in the constellation Perseus, as seen with Planck. This image covers a region of 30x30 degrees. It is a three-colour combination constructed from three of Planck's nine frequency channels: 30, 353 and 857 GHz. Image: ESA/LFI & HFI Consortia.
Both images reveal three physical processes taking place in the dust and gas of the interstellar medium, covering the frequency range of the space telescope. At lowest frequencies emission caused by high-speed electrons interacting with the Galaxy’s magnetic fields is captured, along with an additional diffuse component that comes from spinning dust particles emitting at these frequencies. At intermediate wavelengths of a few millimetres, the emission is from gas heated by newly formed hot stars.
At higher frequencies Planck can pick out the heat emitted by the cold cores of dust clouds, which cocoon the seeds of future stars. Once born, the newborn stars sweep away the surrounding material. This balancing act of cloud collapse and dispersion acts to regulate the number of stars born in our Galaxy, and thanks to Planck's frequency range this process will be explored with greater clarity than ever, because, for the first time, data will be provided on several major emission mechanisms in one go.
The Universe under one roof. European AstroFest returns to London on February 7 & 8, 2014. The UK's favourite astronomy conference and exhibition. Visit the official website site for more details.
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