The Hubble telescope photographs the first moments after the explosion of a supernova

Artist's impression of supernova 1993J in the galaxy M81. / NASA, ESA and G. Bacon

Science | Space

The red superstar exploded more than 11 billion years ago, when the universe was still primitive

The NASA and ESA Hubble Space Telescope has captured the most precise images of a young supernova in the history of the universe, which also show the first moments of a stellar explosion that occurred more than 11,000 million years ago. The observations have also revealed that this red supergiant star was 500 times larger than the Sun, which is the first time that a research team has been able to measure the size of a dying star in the most primitive universe.

"The special thing about this finding is that we have observed the supernova during its first moments, which is only possible with supernovae close to us," explains José María Diego, researcher at the Institute of Physics of Cantabria (IFCA-CSIC-UC) and signatory from work. Furthermore, "detecting a supernova at a very early stage is quite rare, because that stage is very short (only lasts a few hours to a few days) and can easily go unnoticed even for close detection," adds Wenlei Chen, first signer of research and postdoctoral researcher at the University of Minnesota School of Physics and Astronomy.

The image obtained by the Hubble telescope has captured three unique moments of the supernova explosion throughout different phases and has been possible thanks to a phenomenon called 'gravitational lensing'. This effect occurs when halfway between a very distant object (in this case the photographed supernova) and a telescope there is a very large mass, such as a cluster of galaxies thousands of times larger than the Milky Way, these act as a lens and they curve space and light, amplifying and making visible just what is behind.

In this case, the galaxy cluster Abell 370 has acted as that great lens that has magnified the light from the distant supernova behind it, and the magnified images have taken three different routes through the cluster because of the differences in longitude. of the paths followed by the light from the supernova, the slowing down of time and the warping of space due to gravity predicted by Albert Einstein. “Because light takes different times to travel along these three paths, the Hubble image shows three instants of the explosion in a single picture. Among these three instants, one of them corresponds to only a few hours after the explosion”, explains Diego. "My job has been to interpret the gravitational lensing effect and the relative delay times between the different images of the supernova."

Hubble has also captured the changes in temperature of the supergiant star, which are observed with the variation in its color. The bluer, the hotter the supernova, and as it cools, the redder it becomes. “You see different colors in all three images,” says Patrick Kelly, study leader and professor in the University of Minnesota School of Physics and Astronomy. “In the core of the massive star, it collides, it heats up, and then you see it cool down for a week. It's probably one of the most amazing things I've ever seen."

All these findings have been published in the scientific journal 'Nature' and could help the scientific community learn more about the formation of stars and galaxies in the early stages of the universe. Now, taking advantage of the arrival of NASA's James Webb Space Telescope, researchers plan to observe supernovae even further away than this one and create a catalog that will help understand whether stars that existed billions of years ago are different from those in the universe. that we know today.