A new image taken with the Mid-Infrared Instrument (MIRI) onboard the NASA/ESA/CSA James Webb Space Telescope shows streamers of gas and dust studded with star-forming patches in NGC 346, a prominent young cluster in the Small Magellanic Cloud.
This Webb image of NGC 346 traces emission from cool gas and dust. Image credit: NASA / ESA / CSA / STScI / N. Habel, JPL / P. Kavanagh, Maynooth University.
NGC 346 is an open star cluster located about 210,000 light-years away in the constellation of Tucana.
It resides in the Small Magellanic Cloud, a dwarf galaxy that is a satellite of our Milky Way Galaxy.
Also known as ESO 51-10, Kron 39 or Lindsay 60, NGC 346 was discovered on August 1, 1826 by the Scottish astronomer James Dunlop.
The cluster has a diameter of 150 light-years and a mass of 50,000 solar masses.
“The Small Magellanic Cloud is a satellite galaxy of the Milky Way, visible to the unaided eye in the southern constellation Tucana,” Webb astronomers said.
“This small companion galaxy is more primeval than the Milky Way in that it possesses fewer heavy elements, which are forged in stars through nuclear fusion and supernova explosions, compared to our own Galaxy.”
“Since cosmic dust is formed from heavy elements like silicon and oxygen, we expected the Small Magellanic Cloud to lack significant amounts of dust.”
“However the new MIRI image, as well as a previous image of NGC 346 from Webb’s Near-Infrared Camera (NIRCam), show ample dust within this region.”
In the MIRI image, blue tendrils trace emission from material that includes dusty silicates and sooty chemical molecules known as polycyclic aromatic hydrocarbons (PAHs).
“More diffuse red emission shines from warm dust heated by the brightest and most massive stars in the heart of the region,” the astronomers said.
“An arc at the center left may be a reflection of light from the star near the arc’s center. Similar, fainter arcs appear associated with stars at lower left and upper right.”
“Lastly, bright patches and filaments mark areas with abundant numbers of protostars.”
The researchers looked for the reddest stars, and found 1,001 pinpoint sources of light, most of them young stars still embedded in their dusty cocoons.
“By combining Webb data in both the near-infrared and mid-infrared, we are able to take a fuller census of the stars and protostars within this dynamic region,” they said.
“The results have implications for our understanding of galaxies that existed billions of years ago, during an era in the Universe known as ‘cosmic noon,’ when star formation was at its peak and heavy element concentrations were lower, as seen in the Small Magellanic Cloud.”
