In the nebula, which lies around 6,500 light-years from Earth, hot newborn stars that formed from clouds of hydrogen gas shine brightly with ultraviolet light. This intense radiation in turn excites the surrounding hydrogen cloud, making it glow a distinctive shade of red. This red shade is typical of star-forming regions.
Some people see a chicken shape in pictures of this red star-forming region, giving the nebula its nickname — though there is some disagreement over exactly which part of the nebula is chicken-shaped, with various bird-like features in evidence across the picture.
Aside from the glowing gas, another sign of star formation in IC 2944 is the series of opaque black clumps silhouetted against the red background in part of this image. These are examples of a type of object called Bok globules. They appear dark as they absorb the light from the luminous background. However, observations of these dark clouds using infrared telescopes, which are able to see through the dust that normally blocks visible light, have revealed that stars are forming within many of them.
The most prominent collection of Bok globules in this image is known as Thackeray’s Globules, after the South African astronomer who discovered them in the 1950s. Visible among a group of bright stars in the upper right part of the image, these globules feature in a famous image taken by the NASA/ESA Hubble Space Telescope (http://www.spacetelescope.org/images/opo0201a).
While Hubble offers greater detail in its image of this small area, the Wide Field Imager on the MPG/ESO 2.2-meter telescope at the European Southern Observatory’s (ESO) La Silla Observatory captures a much larger panorama in its images, covering an area of sky roughly the size of the Full Moon. Much like a zoom lens on a camera lets a photographer choose the most appropriate field of view when taking a picture, the dramatically different viewpoints captured by different telescopes can offer complementary data to scientists studying astronomical objects that cover an extended area of the sky.
If the stars cocooned in Thackeray’s Globules are still gestating, then the stars of cluster IC 2948, embedded within the nebula, are their older siblings. Still young in stellar terms, at just a few million years old, these stars shine brightly, and their ultraviolet radiation provides much of the energy that lights up the nebula. These glowing nebulae are relatively short-lived in astronomical terms — typically a few million years — meaning that the Lambda Centauri Nebula will eventually fade away as it loses both its gas and its supply of ultraviolet radiation.
