Multi-megapixel image brings open star cluster into sharp focus
The European Southern Observatory (ESO)has released a colossal 615 megapixel visible light image of astunning collection of bright young stars that make up the Messier 18open cluster. By observing the cluster, which is located around 4,600light-years from Earth in the constellation of Sagittarius,astronomers can test their understanding of how stars evolve, andeventually die, often giving rise to the next generation of stellarbodies.
Messier 18 forms part of the over 100 strong Messiercatalog of astronomical objects that were discovered by 18th century astronomer Charles Messier as he scoured the night sky in search ofundiscovered comets.
Also referred to as NGC 663, the hiveof brightly colored stars contained in the image form part of astellar group known as an open cluster. Over a thousand of these relatively loose star formations have already been discovered, which, havingformed from the same cloud of interstellar gas, share exactly thesame make up, and vary significantly only in terms of their masses.
The ability to observe large numbers ofstars that sit at the same distance from Earth, and share so manycharacteristics, presents astronomers with a fantastic opportunity toobserve the evolution and and death of stellar bodies such as our ownSun.
It is believed that our Sun was createdin an open cluster. Over time, the powerful stellar winds created byour young Sun and its siblings blasted away the surrounding clouds ofleftover gas and dust, which in turn weakened the gravitationalbinding that held the stellar bodies together. The tumultuousgravitational influence of the surrounding stars could then haveworked to eject our Sun, and others like it, dispersing the starsacross our region of the Milky Way.
The newly-released image of Messier 18was captured by the 2.6 m (8.5 ft)VLT Survey Telescope (VST) located at the ESO's ParanalObservatory in Chile. The VST is currently the largest operational telescope in the world designed to survey large areas of the sky in the visible light spectrum, boasting a field of view as broad as two full Moons. The cutting edge telescope is equippedwith a 268 megapixel camera, and capable of imaging the cosmos in awide range of wavelengths from ultraviolet through to near-infrared.
The 30,577 x 20,108pixel beast of an image is characterized by clouds of glowing red gaspeppered with bright, white and blue stars, along with the occasionaldark filaments of cosmic dust that work to absorb the light emittedby cosmic wonders lurking behind.
The blue and white colors of the starsindicate that the cluster is a mere 30 million years old, whichmakes it an infant in the context of the other open clustersdiscovered scattered around the Milky Way. These young, powerfulstars are responsible for the red glow of the surrounding gas, as thedeluge of ultraviolet light thrown out by the super hot stars stripsthe clouds of the electrons, causing them to emit their own reddishlight in the process.
The video below shows the cluster.