Thackeray's Globules in IC 2944

Thackeray's Globules in IC 2944, a photo by Hubble Heritage on Flickr.

Via Flickr:
Strangely glowing dark clouds float serenely in this remarkable and beautiful image taken with NASA's Hubble Space Telescope. These dense, opaque dust clouds - known as "globules" - are silhouetted against the red glow of hydrogen gas and bright stars in the busy star forming region, IC 2944. These globules were first found in IC 2944 by astronomer A.D. Thackeray in 1950.

Although globules like these have been known since Dutch-American astronomer Bart Bok first drew attention to such objects in 1947, little is known about their origin and nature, except that they are generally associated with large areas of star-formation, called "HII regions" due to the presence of hydrogen gas.

The largest of the globules in this image is actually two separate clouds that overlap along our line of sight. Each cloud is nearly 1.4 light-years (50 arcseconds) along its longest dimension, and collectively, they contain enough material to make more than 15 stars like our Sun. IC 2944, the surrounding HII region, is filled with gas and dust that is illuminated and heated by a loose cluster of O-type stars. These stars are much hotter and more massive than our Sun. IC 2944 is relatively close by, located only 5900 light-years (1800 parsecs) away in the constellation Centaurus.

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