Right place, right time: Hubble telescope captured a supernova as it exploded

Talk about being at the right place at the right time.

In 2010, the Hubble Space Telescope captured several images of the Abell 370 galaxy cluster. In itself, that's hardly a groundbreaking feat. But a team of astronomers systematically reviewing archival Hubble images discovered something incredible in those images: an image of an infant supernova that exploded some 11.5 billion years ago, taken just hours after the star's death.

The team, led by postdoctoral researcher Wenlei Chen of the University of Minnesota, was looking for gravitationally lensed, transient events, and that's exactly what the supernova is. It's hidden behind Abell 370, but because light bends around the galaxy cluster due to its gravitational force — an effect known as gravitational lensing — we can actually see it from our vantage point, albeit in a warped manner.

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The left panel shows the portion of Abell 370 where the multiple images of the supernova appeared. Panel A, a composite of Hubble observations from 2011 to 2016, shows the locations of the multiply-imaged host galaxy after the supernova faded. Panel B, a Hubble picture from December 2010, shows the three images of the host galaxy and the supernova at different phases in its evolution. Panel C, which subtracts the image in Panel B from that in Panel A, shows three different faces of the evolving supernova. Using a similar image subtraction process for multiple filters of data, Panel D shows the different colors of the cooling supernova at three different stages in its evolution. (Image credit: NASA, ESA, STScI, Wenlei Chen (UMN), Patrick Kelly (UMN), Hubble Frontier Fields)

Inputting the Hubble data into models and analyzing details in the images like brightness and color, Chen and his team determined that the original star that had gone supernova was likely a red supergiant with a diameter approximately 530 times that of the sun.

They also determined that the first image in the series of three was taken by Hubble just six hours after the explosion following the core collapse, with the second and third being taken about 10 and 30 days after the explosion, respectively.

And because the supernova has high redshift — the wavelengths of light are stretched and shifted towards the red side of the spectrum due to the expansion of the universe — the astronomers were able to estimate the supernova's age to approximately 11.5 billion years old, making it one of the oldest and most distant supernovas we've ever seen. 

The team hopes that their modeling will aid the study of similar distant supernovas, should they be discovered. Those discovered, in turn, would be able to progress the study of stellar populations at high redshift.

A paper based on this research was published in the journal Nature today.

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Stefanie Waldek
Contributing writer

Space.com contributing writer Stefanie Waldek is a self-taught space nerd and aviation geek who is passionate about all things spaceflight and astronomy. With a background in travel and design journalism, as well as a Bachelor of Arts degree from New York University, she specializes in the budding space tourism industry and Earth-based astrotourism. In her free time, you can find her watching rocket launches or looking up at the stars, wondering what is out there. Learn more about her work at www.stefaniewaldek.com.