The Jewel Box NGC 3603

Posted on Friday, 5 September, 2014Sunday, 20 August, 2017 by Zheluo Cai

Thousands of sparkling young stars nestled within the giant nebula NGC 3603. This stellar “jewel box” is one of the most massive young star clusters in the Milky Way Galaxy, and is in the Carina-Sagittarius spiral arm of the Milky Way, about 20,000 light-years from the Solar System, and spans roughly 17 light-years. The nebula was discovered by Sir John Herschel in 1834, during his visit to South Africa.

This image shows a star cluster surrounded by a vast region of bluish dust and gas – the raw material for new star formation. This environment is not as peaceful as it looks, as powerful ultraviolet radiation and violent stellar winds from the cluster’s largest stars have blown out an enormous cavity in the gas-and-dust cloud, providing an unobstructed view of the cluster.

The swirling nebula of NGC 3603 contains around 400,000 solar masses of gas. Lurking within this vast cloud are a few Bok globules, named after Bart Bok, who first observed them in the 1940s. Bok globules, resembling insect cocoons, are dark clouds of dense dust and gas with masses of about ten to fifty times that of the Sun. They are in the process of collapsing under their own weight, forming new stars. Giant pillars of gas can also be seen extending away from the central cluster.

In this infrared image taken by NASA’s Wide-field Infrared Survey Explorer (WISE), the center of the image is a giant star cluster dominated by hot, massive stars. The bright star at the upper right edge of the central cluster (see inset) is Sher 25, one of the most massive stars in the nebula at a late stage of its life. Sher 25 is a blue supergiant star in the located approximately 25,000 light years from our Sun and has an apparent magnitude of 12.2. Its initial main sequence mass is calculated at 60 times the mass of our Sun, but a star of this type will have already lost a substantial fraction of that mass. The name derives from the original cataloguing of stars in NGC 3603 by David Sher. This rapidly aging star is surrounded by a unique ring of glowing gas. It will end its life in a powerful supernova blast within the next million years. A faint, wispy blue ring of gas surrounds this massive, aging star.

These WISE observations provide circumstantial evidence that the massive stars in the center of the cluster triggered the formation of younger stars in the halo, which can be seen as red dots. The dust at the center of the cluster is very hot, producing copious amounts of infrared light, which results in the bright, yellow cores of the nebulosity.