January 16, 2013
Astronomers Capture Rare Glimpse Of Star-Forming Region In Visible Light
Lawrence LeBlond for redOrbit.com - Your Universe OnlineThe European Southern Observatory (ESO) released a stunning new image of a dark cloud where new stars are forming, along with a cluster of brilliant stars that have already emerged from the stellar nursery.
The new image, taken with MPG/ESO 2.2-meter telescope at La Silla Observatory in Chile, is one of the finest and clearest ever taken in visible light of this little-known region.
As seen in the image, a dark column resembling smoke billowing from a smokestack appears to the left of a group of brilliantly lit stars. While the two features are distinctly dissimilar from one another, astronomers note they are in fact closely linked. The dark cloud actually contains huge amounts of cool cosmic dust where new stars are born. Astronomers speculate that our own Sun formed in a similar star forming region more than 4 billion years ago.
This dark star-birthing cloud is known as Lupus 3 and is found about 600 light years from Earth in the constellation Scorpius (The Scorpion). Lupus 3 is about five light years across and is one of the closest stellar nurseries to our own Sun.
Typically dusty clouds block radiation emitted from these newborn stars and astronomers can only detect those using longer wavelengths than visible light. But as the stars get hotter and brighter their intense radiation and stellar winds gradually burn away the clouds around them and emerge for a spectacular showing.
The bright stars seen in the new image (just right of the center) form a perfect example of a group of such hot, bright young stars. Some of the brilliant blue light is seen being scattered off the remaining dust around them. The two brightest stars are bright enough to be seen easily with a small telescope or binoculars. These young stars are still encircled with glowing gas and have not yet begun nuclear fusion, allowing them to shine brightly on their own. Astronomers surmise that these stars are still less than a million years old.
Although these young, brightly glowing stars are less obvious at first glance than the bright blue ones around them, surveys have found even younger stellar objects in this star-forming region.
Star-forming regions can be immense, such as the Tarantula Nebula where hundreds of massive stars are being formed. However, most of the stars found in our galaxy and others are thought to have formed in less expansive regions like Lupus 3, where only two bright stars are visible and no heavy stars have yet formed.
Still, Lupus 3 is one of the most fascinating star-forming regions for astronomers and is a beautiful illustration of the early stages of the life of stars.
The bright stars in this region are known as Herbig Ae/Be stars after the astronomer who first identified them. The A and B refer to the spectral types of stars,, somewhat hotter than the Sun, and the e indicates that emission lines are present in their spectra due to the glow from the gas around them. As these stars contract, they shine by converting gravitational potential energy into heat.