James Webb photographed cluster NGC 346, one of the most dynamic star-forming regions in nearby galaxies. At a distance of 210,000 light-years, it resembles “cosmic noon,” a time when stars were forming in abundance in the universe shortly after the Big Bang.
Pinkish-orange swirls in the Small Magellanic Cloud, a dwarf galaxy near our Milky Way: it’s the cluster NGC 346, stripped of the dust that weighed it down in an image captured by Hubble, less efficient than James Webb for infrared views.
>> The NGC 346 cluster as seen from JWST (left) and Hubble (right):
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This region is teeming with stars in the making and provides scientists with a fabulous window into the past: observing a similar phenomenon at the dawn of our universe, during “cosmic noon” – in English “cosmic noon” – in the formation of stars was widespread at its peak about ten billion years ago. That’s only 2 to 3 billion years after the Big Bang.
NGC 346 — a rare structure — is one of the most dynamic regions for star formation: it contains the building blocks not just of stars, but potentially planets as well.
hydrogen, helium and dust
The Small Magellanic Cloud contains lower concentrations of elements heavier than hydrogen or helium – which astronomers call metals – than those observed in the Milky Way.
Because dust grains in space are mostly metals, scientists expected there would be small amounts of dust and that they would be difficult to detect. But new data from the Webb satellite shows just the opposite.
NGC 346’s gas plumes and arcs contain two types of hydrogen. The pink gas represents energized hydrogen, the temperature of which can reach 10,000°C or more. The orange gas represents much colder, dense molecular hydrogen at around -200°C or colder and its associated dust.
The cooler gas is an excellent environment for star formation: as they form, they change the environment around them. This effect is visible in the various ridges formed as the light from these young stars breaks through dense clouds.
Stellar Erosion
The stars collect gas and dust that appear as ribbons in this image. The numerous columns of glowing gas reflect this stellar erosion across the region.
By observing protostars that are still in the process of formation, researchers can find out whether this process in the Small Magellanic Cloud differs from that observed in our Milky Way.
“We see the building blocks, not only of stars, but possibly also of planets,” says Guido De Marchi of the European Space Agency, co-investigator on the research team. “And because the Small Magellanic Cloud has a galaxy-like environment during cosmic noon, it’s possible that rocky planets formed earlier in the history of the Universe than we thought.”
Stephanie Jaquet