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‘Dancing’ dwarf galaxies spotted by James Webb Space Telescope

David BenjaminDecember 3, 2025

For this new ESA/Webb Picture of the Month, the NASA/ESA/CSA James Webb Space Telescope has spied a pair of dwarf galaxies engaged in a gravitational dance. These two galaxies are named NGC 4490 and NGC 4485, and they???re located about 24 million light-years away in the constellation Canes Venatici (The Hunting Dogs). Aside from the Milky Way???s own dwarf companions (the Large and Small Magellanic Clouds), this is the closest known interacting dwarf-dwarf system where astronomers have directly observed both a gas bridge and resolved stellar populations. Together NGC 4490 and NGC 4485 form the system Arp 269, which is featured in the Atlas of Peculiar Galaxies. At such a close distance (and with Webb???s impressive ability to peer through dusty cosmic clouds) these galaxies allow astronomers to witness up close the kinds of galaxy interactions that were common billions of years ago. Dwarf galaxies likely share many similarities with young galaxies in the early Universe: they are much less massive than galaxies like the Milky Way, they typically have small amounts of metals (what astronomers call elements heavier than helium), and they contain a lot of gas and relatively few stars. When nearby dwarf galaxies collide, merge, or steal gas from one another, it can tell us how galaxies billions of years ago might have grown and evolved.?? The nearby dwarf galaxies NGC 4490 and NGC 4485 form an intriguing pair. Nearly three decades ago, astronomers discovered a wispy bridge of gas connecting the two galaxies, showing that they have interacted in the past. Despite many studies with powerful telescopes like the NASA/ESA Hubble Space Telescope, the history between NGC4490 and NGC 4485 has remained mysterious. Recently, Webb observed this curious galactic pair as part of the Feedback in Emerging extrAgalactic Star clusTers (FEAST) programme (#1783; PI: A. Adamo). The FEAST programme used Webb???s sensitive infrared eyes to reveal the formation of new stars in different types — The NASA/ESA/CSA James Webb Space Telescope has spied a pair of dwarf galaxies engaged in a cosy gravitational dance. These two galaxies are called NGC 4490 and NGC 4485, they’re located about 24 million light-years away in the constellation Canes Venatici (The Hunting Dogs). (Picture: ESA/Webb, NASA & CSA, A. Adamo ()

What is a dwarf galaxy?

A dwarf galaxy is home to just a few billion stars – a number of them orbit lager galaxies, such as the Milky Way or the Andromeda Galaxy. Observing dwarf galaxies merge can teach us how galaxies billions of years ago might have grown and evolved.(Picture: MARIANA SUAREZ/AFP via Getty Images)

Space scientists mark changing of seasons with striking cosmic wonders

The four seasonal images containing X-rays from Chandra along with data from other telescopes. The images (clockwise from top left) are the star-forming region NGC 6334, supernova remnant G272.2-0.3, interacting spiral galaxies NGC 2207 and IC 2163, as well as R Aquarii, which hosts an orbiting pair of stars Space scientists have marked the changing of the seasons with some striking cosmic wonders. NASA???s Chandra X-ray Observatory wanted to wave goodbye to autumn by releasing images of celestial spectacles. They include space oddities, including one resembling a cosy sweater ??? perhaps suitable for Christmas ??? and another they liken to fallen leaves.Chandra says they are examples of pareidolia, the phenomenon that allows people to see familiar patterns or shapes in data. Photo released 02/12/2025 — This isn’t the only beautiful picture taken of space recently either. Beautiful images similar to this have been released from NASA’s Chandra X-ray Observatory, as they dropped images of celestial fanfare to wave goodbye to autumn. They include space oddities, one resembling a cozy sweater – just in time for Christmas – and another they compare to fallen leaves, not a summer’s day. Chandra states they are examples of pareidolia, the phenomenon that allows people to see familiar patterns or shapes in data. (Picture: / SWNS)

NGC 6334: Cosmic Leaves Blowing. Space scientists have marked the changing of the seasons with some striking cosmic wonders. NASA???s Chandra X-ray Observatory wanted to wave goodbye to autumn by releasing images of celestial spectacles. They include space oddities, including one resembling a cosy sweater ??? perhaps suitable for Christmas ??? and another they liken to fallen leaves.Chandra says they are examples of pareidolia, the phenomenon that allows people to see familiar patterns or shapes in data. Photo released 02/12/2025 — They explain: ‘Before fall gives way to winter in the northern hemisphere, NASA’s Chandra X-ray Observatory has several images that celebrate autumn and its many delights to share. In spirit of the season, this collection gathers Chandra data with those from its telescopic family including NASA’s James Webb, Hubble, and Spitzer Space Telescopes, plus others in space and on the ground.’ (Picture: / SWNS)

R Aquarii: A Cosmic Sweater ??? This binary star system forms a structure resembling a cosy sweater, with X-rays and optical light tracing jets from a white dwarf pulling material from a red giant companion, twisting and looping in space. Space scientists have marked the changing of the seasons with some striking cosmic wonders. NASA???s Chandra X-ray Observatory wanted to wave goodbye to autumn by releasing images of celestial spectacles. They include space oddities, including one resembling a cosy sweater ??? perhaps suitable for Christmas ??? and another they liken to fallen leaves.Chandra says they are examples of pareidolia, the phenomenon that allows people to see familiar patterns or shapes in data. Photo released 02/12/2025 — As for the dwarf galaxy, aside from the Milky Way’s own dwarf companions (the Large and Small Magellanic Clouds), this is the closest known interacting dwarf-dwarf system where astronomers have directly observed both a gas bridge and resolved stellar populations. The nearby dwarf galaxies NGC 4490 and NGC 4485 form an intriguing pair. (Picture: / SWNS)

G272: The Space Pumpkin ??? The supernova remnant G272.2-03.2 resembles a glowing cosmic pumpkin, with Chandra X-rays showing superheated gas inside the shell created by a Type Ia thermonuclear explosion from a white dwarf star that destroyed its companion. Space scientists have marked the changing of the seasons with some striking cosmic wonders. NASA???s Chandra X-ray Observatory wanted to wave goodbye to autumn by releasing images of celestial spectacles. They include space oddities, including one resembling a cosy sweater ??? perhaps suitable for Christmas ??? and another they liken to fallen leaves.Chandra says they are examples of pareidolia, the phenomenon that allows people to see familiar patterns or shapes in data. Photo released 02/12/2025 — Nearly three decades ago, astronomers discovered a wispy bridge of gas connecting these two galaxies, showing that they have had interactions in the past. Despite many studies with powerful telescopes like the NASA/ESA Hubble Space Telescope, the history between NGC4490 and NGC 4485 has remained largely unknown. (Picture: NASA/SAO/CXC et al. / SWNS)

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