Posted: October 22, 2008
A new ESO image reveals the vast stellar nursery of Gum 29, which hosts a small cluster of stars bearing one of the most massive double star systems known to man.
This image was obtained with the Wide Field Imager (WFI) camera attached to the 2.2-metre Max-Planck/ESO telescope through four different filters (B, V, R, and H-alpha), and shows the amazing intricacies of the vast stellar nursery Gum 29. At its centre lies the cluster of young stars Westerlund 2. Image: ESO.
Gum 29, named for it being the 29th entry in astronomer Colin Stanley Gum’s catalogue, is a vast region of ionised hydrogen gas that spans over 200 light years. Known as the H-II region, the hydrogen gas has been stripped of its electrons by the intense breath of hot young stars radiating in its centre. The new image was captured with the Wide Field Imager (WFI) camera attached to the 2.2 metre Max-Planck telescope at the European Southern Observatory (ESO)’s La Silla site in Chile.
A young and little-known star cluster – Westerlund 2 – is embedded within the belly of Gum 29 at a distance of 26,000 light years from Earth, corresponding to a location within the outer edge of the Carina spiral arm of our Milky Way Galaxy. It is thought to be just one or two million years old. Two stars in the bottom right of Westerlund 2 form a double star system of huge proportions at 82 and 83 times the mass of our Sun respectively, and rotating around each other in approximately 3.7 days. They are amongst the most massive stars known to astronomers.
Marked in the image is a double stellar system in the Westerlund 2 cluster. The two stars have masses of 82 and 83 times that of our Sun and are amongst the most massive stars known to astronomers. Image: ESO.
Intense scrutiny of this pair has also revealed their identity as Wolf-Rayet stars, massive stars that are expelling huge quantities of material as they near the end of their lives. Observations made in X-rays have subsequently shown that streams of material from each star continually collide, creating a blaze of X-ray radiation.