Oh dear, a relatively close neighbor of ours—the spiral galaxy NGC 7714—has drifted too close to another nearby galaxy, and now its spindly arms are all twisted out of shape and long streams of its stellar material have been dragged out into space. The Hubble Space Telescope captured the dramatic interaction of this merging pair, which astronomers are calling Arp 284.
NGC 7714 is 100 million light-years from Earth, and it’s a typical Wolf-Rayet starburst galaxy. That means the extremely hot and bright stars within the galaxy began their lives with dozens of times the mass of our sun—but they quickly lose most of it due to strong winds.
Based on these newly released Hubble images, NGC 7714 has witnessed some violent events in its recent past. According to a European Space Agency (ESA) release, the tell-tale signs of brutality can be seen in NGC 7714's misshaped arms and the smoky, golden haze stretching out from the center of the galaxy. Sometime between 100 and 200 million years ago, NGC 7714 drifted too close to a smaller companion galaxy named NGC 7715, and the two began disfiguring each other’s structure and shape.
The ongoing merger has created a ring and two long tails of stars emerging from NGC 7714. These make up a bridge between the two galaxies, acting as a pipeline to funnel material from NGC 7715 towards its much larger companion and triggering bright bursts of star formation. Most of the bustle of star-forming activity is happening at the galactic center, but new stars are also being sparked throughout the whole galaxy.
The smaller companion NGC 7715 lies just outside the frame of the composite image above (it would be off the top of the image), but you can see both of the galaxies below in this wider-field image from the Digitized Sky Survey. (The bright star on the left is around a billion times closer than the galaxy.)
Images: ESA, NASA with acknowledgement to A. Gal-Yam/Weizmann Institute of Science (top), NASA, ESA, Digitized Sky Survey 2 (bottom)
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