More than 160,000 years ago , a white dwarf went supernova in the nearby dwarf galaxy we call the Large Magellanic Cloud . Its light passed through space and reached Earth about 670 years ago. That’s the new estimate astronomers have come up with. This supernova exploded during the Hundred Years’ War between France and England in the longest war conflict in Europe.
Astronomers examined light from a Type Ia supernova explosion that created supernova remnant SNR 0519-69.0 in the Large Magellanic Cloud, a satellite galaxy of the Milky Way visible from the southern hemisphere.
The study, led by researchers at NASA’s Goddard Space Flight Center, and published in The Astrophysical Journal, shows that SNR 0519-69.0 is 164,000 light-years away in the constellations of Dorado and Mensa.
“SNR 0519-69.0 is the remains of an exploding white dwarf star,” explains Brian Williams of NASA’s Goddard Space Flight Center, co-author of the paper. “After reaching a critical mass, either by extracting matter from a companion star or by merging with another white dwarf , the star suffered a thermonuclear explosion and was destroyed. Scientists use this type of supernova, called Type Ia, for a wide range of scientific studies ranging from studies of thermonuclear explosions to measuring distances to galaxies across billions of light-years.”
Clues to turn back the cosmic clock
This accompanying image is a composite snapshot showing X-ray data from NASA’s Chandra X-ray Observatory and optical data from NASA’s Hubble Space Telescope. X-rays from SNR 0519 with low, medium, and high energies can be seen in shades of green, blue, and purple, respectively, and some of these colors overlap (and appear white).
The astronomers combined the data from the Chandra (X-ray observation) and Hubble (optical data) telescopes, with data from the Spitzer Space Telescope (infrared observation, like the brand new James Webb) -already ‘retired’- of NASA, to determine how long ago the star in SNR 0519 exploded. After also comparing Hubble images from 2010, 2011 and 2020 to measure the velocities of material in the explosion’s blast wave, which range from about 6 million kilometers to 9 million kilometers kilometers per hour, determined that the light from the explosion would have reached Earth about 670 years ago.
Thus, in the stellar evolution movie this would have happened during the Hundred Years War between England and France, with the famous victory of the Battle of Poitiers and the heyday of the Ming dynasty in China. Similarly, the Black Death also made its first appearance in Europe around this time. All the inhabitants of that time, taking the 1350s as a reference, would have potentially seen the spectacular supernova in the sky. According to experts, it would have been visible to the naked eye as it was a type Ia supernova.
The authors found that the brightest X-ray regions of the remnant are where the slower-moving material is found, and no X-ray emission is associated with the faster-moving material. These results imply that part of the blast wave crashed into the dense gas around the remnant, causing it to slow down as it traveled. Astronomers can use additional observations with Hubble to determine more precisely when the time of the star’s disappearance should actually be established.
“Young remnants like this need to be continuously monitored,” the researchers said.
Referencia: Brian J. Williams et al. 2022. Evidence for a Dense, Inhomogeneous Circumstellar Medium in the Type Ia SNR 0519-69.0. ApJ The Astrophysical Journal 935, 78; doi: 10.3847/1538-4357/ac81ca