Webb captures a stunning image of Cartwheel Galaxy, revealing critical details about star formation

by Jeremy Gray

posted Thursday, August 4, 2022 at 6:00 PM EDT

It’s time to check out a brand-new image from the $10B James Webb Space Telescope. Scientists have revealed a brilliant new image of the Cartwheel Galaxy, revealing important new details about star formation.

The Cartwheel Galaxy, also known as ESO 350-40 or PGC 2248, is a lenticular galaxy and ring galaxy located roughly 500 million light-years from Earth in the Sculptor constellation. Its unusual, wheel-like appearance is due to a high-speed collision between a large spiral galaxy and a smaller galaxy that isn’t visible. Due to the collision, the galaxy has two rings, a bright inner ring, and a larger colorful surrounding ring. They emanate from the center of the collision, “like ripples in a pond after a stone is tossed into it.” Ring galaxies like this are much rarer than spiral galaxies like the Milky Way.

The bright core includes a lot of hot dust, and its brightest areas are home to gigantic young star clusters. The outer ring, which has been expanding for the last 440 million years or so, is “dominated by star formation and supernovas.” As the ring continues to expand, it interacts with the surrounding gas, instigating star formation.

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The image above is a composite that includes data gathered by Webb’s primary imager, the Near-Infrared Camera (NIRCam), and Webb’s Mid-Infrared Instrument (MIRI). NIRCam observes in the near-infrared range from 0.6 to 5 microns, revealing even more stars than you can see in visible light. Young stars, many of which are forming in the Cartwheel Galaxy’s outer ring, are less obscured by dust when viewed in infrared light. The many blue dots are individual stars or pockets of star formation. NASA writes, “NIRCam also reveals the difference between the smooth distribution or shape of the older star populations and dense dust in the core compared to the clumpy shapes associated with the younger star populations outside of it.”

As for MIRI, it helps Webb see through the dust in the galaxy. MIRI data are colored red in the composite image. MIRI reveals “regions within the Cartwheel Galaxy rich in hydrocarbons and other chemical compounds, as well as silicate dust, like much of the dust on Earth.” The regions look like red spokes in the image above, forming the galaxy’s skeleton.

The spokes were visible in observations performed by the Hubble Space Telescope, but Webb’s image shows significantly greater detail and fidelity. Plus, you can, simply put, see more thanks to Webb’s NIRCam and MIRI imagers.

Alongside the composite image, the Webb team also released the individual image made using the Mid-Infrared Instrument (MIRI). Of the image, NASA writes, “This image from Webb’s Mid-Infrared Instrument (MIRI) shows a group of galaxies, including a large distorted ring-shaped galaxy known as the Cartwheel. The Cartwheel Galaxy, located 500 million light-years away in the Sculptor constellation, is composed of a bright inner ring and an active outer ring.While this outer ring has a lot of star formation, the dusty area in between reveals many stars and star clusters.” MIRI resolves the dusty regions with fidelity. The young stars in the galaxy energize the dust, causing the orange glow observed in the image.

There’s also an image captured using only NIRCam, which looks a lot like Hubble’s observation, albeit with significantly greater detail.

Finally, you can see the composite image with a compass, scale, and filter information for both of the imaging instruments that were used.

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