Jacinta Bowler
Jacinta Bowler is a science journalist at Cosmos.
They were published in the Best Australian Science Writing 2023.
A striking new image from the James Webb Space Telescope (JWST) has given scientists unprecedented detail on a star forming region near the heart of the Milky Way.
The area – Sagittarius C – is just 300 light years away from the supermassive black hole at the centre of the Milky Way, Sagittarius A* and is around 26,000 light years from Earth.
“There’s never been any infrared data on this region with the level of resolution and sensitivity we get with Webb,” says the observation team’s principal investigator Samuel Crowe, from the University of Virginia. ”So we are seeing lots of features here for the first time”.
“Webb reveals an incredible amount of detail, allowing us to study star formation in this sort of environment in a way that wasn’t possible previously.”
The pink area surrounded by blue on the left of the image is a cluster of protostars – stars which are still forming. Surrounding it in blue is ionised hydrogen, and the large darker section above is an infrared dark cloud.
It’s this pink region that the researchers are most interested in. These stars are collecting dust and gas from the surroundings, to burn. This produces outflows of gas and dust emerging from the dark infrared cloud.
At the centre of the cluster is a massive protostar called G359.44-0.102 which is 30 times the mass of our Sun.
Rubén Fedriani, a co-investigator of the project at the Instituto Astrofísica de Andalucía in Spain says the galactic centre is a crowded, tumultuous place.
“There are turbulent, magnetised gas clouds that are forming stars, which then impact the surrounding gas with their outflowing winds, jets, and radiation,” he says.
“Webb has provided us with a ton of data on this extreme environment, and we are just starting to dig into it.”
The image was taken by the NIRCam (Near-Infrared Camera) instrument aboard the JWST in late September, and the whole image is about 22 light years across.
As is typical in these types of images, the colours are assigned for each grayscale image from a separate infrared filter. In this case there are four filters, corresponding to dark blue, cyan, orange and red.
Because the galactic centre is cosmically quite close to Earth, it allows the JWST to be able to study individual protostars. This means researchers can find out more information on how stars form – particularly in areas as dense as the galactic centre.
“The image from Webb is stunning, and the science we will get from it is even better,” Crowe says.
“Massive stars are factories that produce heavy elements in their nuclear cores, so understanding them better is like learning the origin story of much of the Universe.”