One of the galaxy’s most massive young star clusters is revealed in a stunning new image from the Hubble Space Telescope.
The star-forming nebula NGC 3603 lies in the Carina spiral arm of our galaxy (Video: ESA/M Kornmesser/L L Christensen/R Gendler/M Pugh/Astromania de Yave)
Some of the heaviest known stars in the galaxy reside in this massive young cluster imaged by the Hubble Space Telescope (Image: NASA/ESA/STScI/AURA)
The cluster of thousands of stars lies 20,000 light years from Earth in the Carina spiral arm of our galaxy. It is embedded in a star-forming nebula called NGC 3603, a cloud of gas and dust with enough material to form 400,000 stars like the Sun. Watch a video zooming in on the star cluster’s location in the sky by clicking on the image at right.
Most of the bright stars in the image are very hot and massive. Their radiation and stellar winds have blown out a large cavity in the nebula around them.
The three brightest ones at the heart of the cluster had previously appeared to be more massive than theory allows. But the Hubble investigation, led by Jesús Maíz Apellániz of the Instituto de Astrofísica de Andalucía in Granada, Spain, hints that each of these objects may actually be a blurring of light from two or more individual stars that are too close together to be observed as separate objects.
Previous measurements by Hubble and the Very Large Telescope (VLT) in Chile had come to the same conclusion for two of these star systems, indicating that the heaviest star involved is as massive as 114 Suns, which is at the borderline of what some theoretical models allow.
The new investigation also indicates that the most massive stars have gathered at the cluster’s centre, something that has previously been observed in more massive groupings called globular star clusters. Globular clusters behave like cosmic sorting machines. Over time, interactions between the stars cause the most massive ones to settle near the centre of clusters, while less massive stars stay farther out.
Also appearing in the image are some dark and extremely cold “Bok globules” at top right. Bok globules are dense clouds of dust and gas with between 10 and 50 times the mass of the Sun. Among the coldest objects known in the universe, with temperatures just a few degrees above absolute zero, they are thought to be condensing and on their way to forming new stars.