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The James Webb Space Telescope has been wowing astronomers since it came online last year, capturing awe-inspiring images of nebulae, stars, and galaxies. It’s also the ideal platform to study dust, which is more interesting than it sounds. The telescope has just beamed back images of WR 124, a rare type of star that could help scientists understand why there’s so much dust in the universe.
WR 124 is what’s known as a Wolf–Rayet star, a phase of life that only a small number of massive stars experience. This is usually the last stop for a star before it explodes in a supernova, characterized by high temperatures and the production of enormous clouds of interstellar dust. Astronomers studying Wolf–Rayet stars previously lacked high-fidelity data, but Webb is perfect for this work.
Wolf–Rayet stars are near the end of their brief lives, having exhausted their hydrogen supply. They fuse heavier elements and eject vast quantities of material into space around them. This dust forms a nebula around the star—the one around WR 124 is known as M1–67. The dust cools as it expands, glowing in infrared. The Webb Telescope is tuned to observe in infrared, revealing previously unseen details in M1–67.
Webb’s Near-Infrared Camera (NIRCam) can resolve the roiling waves of faint dust and gas surrounding the nebula without being overwhelmed by the luminous, super-hot star in the center. Meanwhile, the telescope’s Mid-Infrared Instrument (MIRI) reveals the clumpy structure of the ejected material.
Left: WR 124 as seen by Hubble with many features blocked by dust, Right: WR 124 as seen by Webb shows greater detail
Credit: NASA
Wolf–Rayet stars are a potential way to balance the universe’s “dust budget.” According to NASA, we cannot currently account for the amount of dust we see in the universe, but objects like WR 124 release a great deal of material before exploding. And dust isn’t just an inert curiosity among the stars—they help form stars, planets, asteroids, and any other collection of matter drifting around in the void. The heavy elements and complex molecules contained in cosmic dust are also believed to be key to the development of life as we know it.
WR 124 is about 30 times the sun’s mass, and it’s already lost 10 solar masses during this turbulent phase. Astronomers expect this will last a few hundred thousand years, and then WR 124 will go supernova. Analysis with Webb could help determine if the dust will likely survive the explosion. If so, that would go a long way toward understanding the dust budget surplus.
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