Image Credit: ESA/PACS/SPIRE/Martin Hennemann & Frédérique Motte, Laboratoire AIM Paris-Saclay, CEA/Irfu – CNRS/INSU – Univ. Paris Diderot, France
Cygnus-X is a massive star-forming region of more than 600 light-years across and a mass of 3 million solar masses, located about 4,600 light-years away from Earth in the constellation of Cygnus, the Swan.
This molecular cloud, where thousands of stars are being born, is the largest known star-forming region in the entire Milky Way Galaxy. Its intense star formation activity is resulting in an exceptionally abundant production of massive stars. Although an even larger number of low-mass stars are forming throughout this stellar nursery, it is the presence of so many massive stars, with their powerful winds and copious amounts of ionizing radiation released into their surroundings, that sculpts most of its structure.
Cygnus-X is also home to a very large number of massive protostars as well as a giant OB association (in the central-lower part, to the lower-right of the diffuse blue glow). An OB association, or a loose stellar group contains many young, massive stars of types O and B. This specific association, known as Cygnus OB2, has a mass of up to 100,000 solar masses and hosts up to 2,600 OB type stars. Although they are not visible in the image their effects on the nearby clouds stand out clearly. (The diffuse blue glow visible in the central portion of the image is the result of powerful winds and radiation from the stars in the Cygnus OB association, which have partly cleared out and heated up the surrounding material, making it shine.)
The intricate network of filaments and pillars in the right part of the image may be harbouring the formation of a new, rich OB association, thus showing how Cygnus OB2 might have looked in its infancy, about 3 million years ago.
Several bubbles, or cavities, in the dust and gas are also visible in the image: these are being carved by nearby massive young stars. The radiation released by these stars are causing the bubbles to shine brightly. The expanding bubbles sweep up gas and sometimes even collide, frequently creating regions dense enough to gravitationally collapse into yet more stars. However, this violent process not only triggers the birth of stars but also the death of stars because the massive stars die young in supernova explosions.
As well as the bright regions associated with the formation of very massive stars, there is a network of red and yellow filaments stretching across the image. This material is colder, but the small red clumps are the initial stages of the star formation. However, in a few million years, calm will likely be restored and a large open cluster of stars will remain — which itself will disperse over the next 100 million years.
This image, taken on May 24, 2010, and December 18, 2010 with ESA’s Herschel Space Observatory, combines data acquired with the PACS instrument at 70 micron (shown in blue) and 160 micron (shown in green) and with the SPIRE instrument at 250 micron (shown in red).
The brightest, yellow-white regions are warm centers of star formation. The green shows tendrils of dust, and red indicates other types of dust that may be cooler, in addition to ionized gas from nearby massive stars. North is to the lower-right and east to the upper-right.