Exciting news from the world of astronomy came from NASA’s James Webb Space Telescope in early January, with new data revealing fresh insights into the processes of early star formation.
The James Webb Space Telescope, also known as Webb, is a large infrared telescope serving thousands of astronomers across the world. It was launched on December 25th 2021, aiming to study all phases of the universe including the formation of stars and solar systems.
One of Webb’s main functions is to help us learn more about star and planet formation. Scientists hope it will enable us to answer questions about how clouds of gas and dust collapse to form stars, and how stars evolve and release the heavy elements into space to be recycled into new stars and planets.
To answer these questions, we need to be able to see into the hearts of the dense, dusty cloud cores where star formation begins. Any telescope powerful enough to see into these cores must be infrared because the dust at the heart absorbs visible light, whereas the infrared light emitted from the core can pierce through the dust to reveal what’s within.
Webb is made up of four main instruments, one of which is the Near InfraRed Spectrograph (NIRSpec). The NIRSpec is designed to observe over 100 objects simultaneously as Webb’s mirror must observe galaxies for hundreds of hours in order to collect enough light to form a spectrum. It is the first spectrograph in space with this multi-object capability.
As the NIRSpec will be observing objects that are far away, it needs to be able to block light from closer objects, just as we often squint to focus on an object when at a distance. To do so, the NIRSpec has a microshutter array – microshutter cells, each as wide as a human hair, can be individually opened and closed to view or block a specific section of the sky.
The main instrument used in this recent discovery is the Near InfraRed Camera (NIRCam); Webb’s main imager which lets astronomers photograph very faint objects around a central bright object. Scientists have used the NIRCam to study NGC 346, which is one of the most dynamic star-forming regions in the Small Magellanic Cloud (SMC), over 200,000 light years from Earth.
So, why are astronomers so interested in the SMC? It is particularly important as it closely resembles the conditions of our early universe, approximately two or three billion years after the Big Bang. This period is known as a ‘cosmic noon’, where star formation was at its highest. NGC 346 has been studied before, but Webb allows astronomers to study lighter-weighted protostars than they have ever before, giving new information on the effects of the birth of stars and the star formation process itself.
When stars form, they gather gas and dust from the surrounding molecular cloud which then collects into a disk to feed the protostar. Previously, gas has been detected surrounding protostars in NGC 246, but Webb’s near-infrared observations have allowed astronomers to detect dust inside them, for the first time ever.
Why is this information so exciting? Guido De Marchi of the European Space Agency, a co-investigator on the research team, explains, says: “We’re seeing the building blocks, not only of stars, but also potentially of planets. And since the Small Magellanic Cloud has a similar environment to galaxies during cosmic noon, it’s possible that rocky planets could have formed earlier in the universe than we might have thought.”
Given what we’ve seen so far from Webb, many cannot wait to see what else it’ll reveal about our universe – perhaps more about the early universe, galaxy and star formations, or even life on other planets.
