NASA Webb reveals star formation in dust cluster ribbons

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NGC 346, one of the most dynamic star-forming regions in nearby galaxies, is full of mysteries. Now, it’s a little less mysterious with new results from NASA’s James Webb Space Telescope.

NCG 346 is located in the Small Magellanic Cloud (SMC), a dwarf galaxy close to our own Milky Way. The SMC contains lower concentrations of elements heavier than hydrogen or helium, which astronomers call metals, than the Milky Way. Since dust grains in space are mostly made up of minerals, scientists expected that there would be small amounts of dust, and that it would be difficult to detect. New data from Webb reveals the opposite.

Astronomers probed this region because the conditions and amount of metals within the SMC are similar to those seen in galaxies billions of years ago, during an era in the universe known as the “cosmic noon,” when star formation was at its peak. About 2 to 3 billion years after the Big Bang, galaxies were forming stars at a frantic rate. The star formation fireworks that then occur still shape the galaxies we see around us today.

“It will not have a galaxy in the cosmic noonday NGC 346 like the Small Magellanic Cloud; it will have thousands” of star-forming regions like this one, said Margaret Mixner, an astronomer at the Universities Space Research Association and principal investigator on the research team. “But even if NGC 346 is now the only massive, strongly star-forming cluster in its galaxy, it offers us a great opportunity to explore the conditions that existed at the time of cosmic noon.”

By observing protostars that are still forming, researchers can see if the star formation process in the SMC is different from what we observe in our own Milky Way galaxy. Previous infrared studies of NGC 346 have focused on protostars heavier than about 5 to 8 times the mass of our sun. said Olivia Jones of the UK’s Astronomy Technology Centre, Royal Observatory Edinburgh, research associate on the programme.

When stars form, they collect gas and dust, which can look like bands in web images, from the surrounding molecular cloud. Matter collects in an accretion disk that feeds the central protostar. Astronomers have detected gas around protostars within NGC 346, but Webb’s near-infrared observations mark the first time they have also detected dust in these disks.

“We’re seeing the building blocks, not only of stars, but also potentially planets,” said Guido De Marchi of the European Space Agency, a co-investigator on the research team. “Since the Small Magellanic Cloud has an environment similar to galaxies during the cosmic noon, it is possible that rocky planets formed much earlier in the universe than we thought.”

The team also has spectral observations from Webb’s NIRSpec instrument that they continue to analyze. This data is expected to provide new insights into the material that accumulates on individual protostars, as well as the environment directly around the protostar.

These results are presented Jan. 11 in a news conference at the 241st meeting of the American Astronomical Society. Observations were obtained as part of the program 1227.

The James Webb Space Telescope is the world’s premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe mysterious structures and the origins of the universe and our place in it. Webb is an international program led by NASA with its partners ESA (European Space Agency) and the Canadian Space Agency.

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