You’re looking at NGC 346, a star cluster 210 light years away that is energetically pumping out new stars from a dense cloud of dust and gas. Between ten and eleven billion years ago, nearly all galaxies in the Universe underwent an era of intense star formation much like what we come across in NGC 346. This particular flurry of stellar birth is poetically nicknamed cosmic noon. Since that time, star formation in the Universe has gradually dwindled, although it nevertheless blazes away in pockets that are small. By examining NGC 346 and other clusters like it, we can discover more about the era of cosmic noon and the evolution of galaxies.
To that end, researchers pointed the James Webb Space Telescope’s NIRCam infrared camera at NGC 346 last year, plus they announced the preliminary findings of theirs at the American Astronomical Society ‘s annual conference on January eleven, 2023.
NGC 346 lies within the Small Magellanic Cloud (SMC), a dwarf galaxy which, as among the Milky Way ‘s closest neighbors, is seen to the naked eye in the Southern Hemisphere. The majority of the SMC is not almost as active as NGC 346, which lack of activity is normal for galaxies in the present day Universe.
Margaret Meixner, principal investigator of the research team, explains that things weren’t always as relaxed.
“A galaxy during cosmic noon wouldn’t have one NGC 346, as the Small Magellanic Cloud does; it would have thousands,” she said. “But even if NGC 346 has become the main and just significant cluster furiously forming stars in the galaxy of its, it provides us a great chance to probe the conditions which were in place at cosmic noon.”
Particularly, the SMC has very low levels of heavy elements (everything heavier than helium and hydrogen). This was also accurate of the early Universe, before stars had had some time to churn out heavier elements through nuclear fusion. The researchers are interested in seeing how star formation in areas without heavy elements might differ from star formation in the heavy-element-rich Milky Way. NIRCam allows them to perform that better than in the past, by picking out small young stars that earlier telescopes have not had the resolution to see. “With Webb, we can probe right down to lighter weight protostars, as tiny as a single tenth of the Sun of ours, to determine if the formation process of theirs is impacted by the reduced metal content,” said Olivia Jones, a co investigator on the system.
Webb also made it possible for them to discover dust in the accretion disk of protostars in the SMC the very first time. That means there’s possible for the formation of rocky planets, rather than just stars and gas giants.
“We’re witnessing the building blocks, not just of stars, but also potentially of planets,” said co investigator Guido De Marchi. “And since the Small Magellanic Cloud features a similar setting to galaxies during cosmic noon, it’s possible that rocky planets might have formed earlier in the Universe than we can try to have thought.”
The team is continuing to put over the information collected, incorporating a spectroscopic analysis which can provide more info about the actual chemical makeup of the content in and around the protostars.
In the NIRCam image, the pink gas is hot, energized hydrogen, even though the orange gas (like in the best left) is chilly, dense, molecular hydrogen. This cold, dense hydrogen is a perfect incubator for star formation. As the stars grow, they load nebula close to them, eroding gas and also developing the ridges and ripples observed all over the cluster.
