A rare combination of three different types of cosmic clouds known as nebulas can be seen in a new image of the Trifid Nebula, a smoldering star factory 5,500 light-years away.
The image, taken by astronomers at the European Southern Observatory (ESO) in Chile, provides a glimpse at the early stages of a star's life, from gestation to first light.
The heat and "winds" of newly ignited, volatile stars stir the Trifid's gas- and dust-filled cauldron; in time, the dark tendrils of matter strewn throughout the area will themselves collapse and form new stars.
The Trifid takes its name from the dark dust bands that trisect its glowing heart.
The French astronomer Charles Messier first observed the Trifid Nebula in June 1764, recording the hazy, glowing object as entry number 20 in his renowned catalogue. Observations made about 60 years later by John Herschel revealed the dividing dust lanes, inspiring the English astronomer to coin the name "Trifid."
Made with the Wide-Field Imager camera attached to the MPG/ESO 2.2-meter telescope at ESO's La Silla Observatory in northern Chile, the new image prominently displays the different regions of the Trifid Nebula as seen in visible light.
In the bluish patch to the upper left, called a reflection nebula, gas scatters the light from nearby, Trifid-born stars. The largest of these stars shines most brightly in the hot, blue portion of the visible spectrum. This, along with the fact that dust grains and molecules scatter blue light more efficiently than red light — a property also responsible for our blue skies and red sunsets — imbues this portion of the Trifid Nebula with an azure hue.
In the round, pink-reddish area typical of an emission nebula, the gas at the Trifid's core is heated by hundreds of scorching young stars so that it emits the red signature light of hydrogen, the major component of the gas.
The gases and dust that crisscross the Trifid Nebula make up the third kind of nebula in this cosmic cloud, known as dark nebulas, courtesy of their light-obscuring effects.
Within these dark lanes, the remnants of previous star birth episodes continue to coalesce under gravity's pull.
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, or "EGG", a feature also seen in the iconic Eagle Nebula, another star-forming region. At the tip of the finger, a knot of dense gas has resisted the onslaught of radiation from the massive star.