One of the most spectacular clouds of dust and gas in the sky, the Trifid Nebula, has been captured by astronomers at the European Southern Observatory.
The giant nebula, thousands of light-years away in the constellation of Sagittarius, is a colourful sight in long-exposure photos.
It got its name from English astronomer John Herschel in the early 19th century, thanks to the dark bands of dust that cross its glowing heart, dividing it into three. Otherwise it is known as Messier 20, the number given to it by French comet hunter Charles Messier when he was drawing up his famous catalogue of fuzzy objects in the sky in 1764.
It is a popular target with for amateur astronomers’ telescopes, although too dim to reveal its magnificent colours. Neither can a casual glance tell the nebula’s true nature – as a huge cosmic incubator where stars are being born.
Astronomers say the Trifid is a rare combination of three types of nebula, revealing the violent environment of freshly formed stars, with further starbirth to come.
The heat and “solar winds” from newly ignited, volatile stars stir the Trifid’s cauldron of gas and dust. In time, the dark tendrils of matter strewn throughout the area will themselves collapse and form new stars.
ESO’s dramatic image was made with the Wide-Field Imager camera on the 2.2-meter Max Planck Gesellschaft or MPG/ESO telescope at La Silla in northern Chile.
The bluish patch to the upper left is a reflection nebula that shines with scattered light mainly from one brilliant blue star born within the nebula.
Below, in the round, pink-red area typical of an emission nebula, the gas at the Trifid’s core is heated by hundreds of scorching young stars until it emits the red signature light of hydrogen, the major component of the gas.
The gases and dust that criss-cross the Trifid Nebula make up the third kind of nebula in this cosmic cloud, known as dark nebulae, courtesy of their light-obscuring effects.
Within these dark lanes, the remnants of previous star birth episodes continue to coalesce under gravity’s relentless attraction, leading eventually to more starbirth.
In the lower part of this emission nebula, a finger of gas pokes out from the cloud, pointing directly at the central star powering the Trifid. This is an example of an evaporating gaseous globule, which is more famously seen in the “pillars of creation” pictured by the Hubble space telescope within the Eagle Nebula.
Last week, ESO revealed another dramatic image portraying the violent way that stars are born.
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