NASA's James Webb Space Telescope (JWST) has revealed two dozen previously unseen newborn stars about 7,500 light years from Earth, according to a new study published in the Monthly Notices of the Royal Astronomical Society. Astronomer Megan Reiter from Rice University and her colleagues discovered these unseen young stars after taking a "deep dive" into one of the first images captured by the JWST, or Webb.
The new study offers a glimpse into the discoveries of the cosmos that will be made with Webb's Near-Infrared Camera (NIRCam), an instrument designed to look through clouds of interstellar dust that have previously blocked astronomers' view of stellar nurseries. Mostly, clouds block astronomers' views of star-forming regions that have stars similar to the Sun.
Reiter, along with researchers from the California Institute of Technology, Queen Mary University in London, the University of Arizona, and the United Kingdom's Royal Observatory in Edinburgh, Scotland, analysed a portion of Webb's first images of the 'Cosmic Cliffs', a star-forming region in the Carina Nebula, which resides in the constellation Carina.
What is ‘Cosmic Cliffs’?
'Cosmic Cliffs' is located in a cluster of stars known as NGC 3324. This star cluster is located roughly 7,600 light-years away from Earth. Webb's NIRCam and Mid-Infrared Instrument (MIRI) captured this star-forming region, images of which NASA revealed in July, 2022. The tallest peaks seen in Webb's image of the 'Cosmic Cliffs' are about seven light-years high.
Scottish astronomer James Dunlop was the first to catalogue NGC 3324. The star-forming region is located at the northwest corner of the Carina Nebula.
In a statement released by Rice University, Reiter said Webb gives astronomers a snapshot in time to see just how much star formation is going on in this corner of the universe that researchers have not been able to see before.
NGC 3324 includes several well-known regions of star formation that astronomers have studied for decades, and many details from the region have been obscured by dust in images captured by the Hubble Space Telescope and other observatories.
Webb's NIRCam is built to peer through the dust in such regions and to detect jets of gas and dust that are ejected from the poles of very young stars.
Findings of the study
As part of the new study, the researchers analysed a region of NGC 3324 where only a few stars had previously been found. They analysed a specific infrared wavelength, 4.7 micrometres, and discovered two dozen previously unknown outflows of molecular hydrogen from young stars.
According to the study, the outflows range in size, with many appearing to emanate from protostars that will eventually become low-mass stars like the Sun.
Reiter said the findings speak both to how good Webb is and how much there is going on even in quiet corners of the universe.
Newborn stars gather material from the gas and dust around them within their first 10,000 years. Also, most young stars eject a fraction of the gathered material back into space in the form of jets that stream out in opposite directions from their poles. Molecular hydrogen is a vital ingredient for baby stars which gets swept by these jets, and is visible in Webb's infrared images.
Nathan Smith from the University of Arizona, one of the co-authors on the paper, said jets like the ones observed in the study are signposts of the most exciting part of the star formation process. They are seen only during a brief window of time when the protostar is actively accreting, he added.
Astronomers often find it difficult to study the accretion period of early star formation because it mostly lasts just a few thousand years in the earliest portion of a star's multimillion-year childhood.
Jon Morse from the California Institute of Technology, another co-author on the paper, said jets like those discovered in the study are a "buried treasure".
Morse said the large size of Webb, and its angular resolution provide a level of sharpness that allows astronomers to see relatively small features, even in faraway regions.