An international research team led by the University of Minnesota has obtained the first detailed look of a supernova at a much earlier stage of the Universe’s evolution.

The team identified multiple detailed images of the red supergiant star using data from the Hubble Space Telescope and the Large Binocular Telescope. The star exploded more than 11 billion years ago. The images show the cooling of star. Plus, they could aid astronomers in determining more about the stars and galaxies in the early Universe.

Based on the data, the team also measured the size of the exploded star. Located about 60 times farther away than any other supernova, the red supergiant was found to be about 500 times larger than the sun.

The team could identify multiple detailed images of the red supergiant because of a phenomenon called gravitational lensing, where mass, such as that in a galaxy, bends light. This magnifies the light emitted from the star.

Patrick Kelly, a lead author of the paper and an associate professor at the College of Science and Engineering, said, “It’s very exciting because we can learn in detail about an individual star when the universe was less than a fifth of its current age, and begin to understand if the stars that existed many billions of years ago are different from the ones nearby.”

“The gravitational lens acts as a natural magnifying glass and multiplies Hubble’s power by a factor of eight. The images we captured show the supernova at different ages, separated by several days. We see the supernova rapidly cooling, which allows us to reconstruct what happened and study how the supernova cooled in its first few days with just one set of images. It enables us to see a rerun of a supernova.”

evolution of the star exploding and cooling
An international research team led by the University of Minnesota Twin Cities has measured the size of a star dating back more than 11 billion years ago using images that show the evolution of the star exploding and cooling. Credit: Wenlei Chen, NASA

The researchers estimated the number of stars exploding when the Universe was only a small portion of its current age by combining this result with another of Kelly’s supernova discoveries from 2014. They discovered that there were probably a lot more supernovae than was initially believed.

Wenlei Chen, the first author of the paper and a postdoctoral researcher at the College of Science and Engineering, said, “Core-collapse supernovae mark the deaths of massive, short-lived stars. The number of core-collapse supernovae we detect can be used to understand how many massive stars were formed in galaxies when the Universe was much younger.”

Journal Reference:

  1. Chen, W., Kelly, P.L., Oguri, M., et al. Shock cooling of a red-supergiant supernova at redshift 3 in lensed images. Nature 611, 256–259 (2022). DOI: 10.1038/s41586-022-05252-5