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Supernova: astronomers have traveled back in time to the explosion of this star!

Astronomers are used to using this type of supernova to measure distances in the Universe. But it was with a completely different objective that they became interested in the supernova SNR 0519 in particular. Because by combining the data about her returned by several instruments, they hoped to be able to go back in time.

The Large Magellanic Cloud is a small spiral galaxy, a satellite of ours, the Milky Way. She hides — rather badly because she is still visible to theeyeeye naked — in the constellationconstellation of the’southern hemispheresouthern hemisphere of the sea bream. At some 160,000 light yearslight years of our Earth. It is precisely in this dwarf galaxydwarf galaxy that the remanentremanent of one supernovasupernova caught the attention of NASA researchers. By combining the data collected by several instruments, they succeeded in tracing the thread of the history of the evolution of this star.

The astronomersastronomers have known for a long time that this supernova, known as SNR 0519, was produced by a white dwarfwhite dwarf — like the one that will eventually become our SunSun, in 5 billion years. Amazing for those who are reputed to be the most stable stars. Except when they begin to accrete mattermatter of a companion star. Or that they collide with another white dwarf. A thermonuclear explosion then occurs and a cloud of debris shines in the sky for several weeks. Forming a Type Ia supernova, as researchers call them.

This type of supernova is not uncommon. Astronomers also use them as distance indicators in theUniverseUniverse. Because they all tend to produce somewhat the same amount of light. This means that if an Ia supernova appears weaker to us than another, it is because it is further away from our Earth.

Data from multiple instruments

In an attempt to determine when the fatal explosion that led to supernova SNR 0519 occurred, astronomers from the NasaNasa gathered the data collected by the observatory of X-raysX-rays Chandra, by the Hubble Space Telescope and by the Space Telescope infraredinfrared Spitzer. For a more accessible reading, they colored the bass x-rays energyenergy in green, medium-energy X-rays in blue and high-energy X-rays in purple. When these x-rays overlap, the render appears white. Optical data is colored red.

Supernova: this star exploded inside another!

The researchers first wanted to determine how speedspeed the materials were moving in the shock wave of SNR 0519. Thanks to images taken by Hubble between 2010 and 2020. They estimated the speed of movement of the supernova debris at something between 6 and 9 million kilometers per hour ! From what to conclude that the light of the explosion reached our Earth at the earliest about 670 years ago. During the Hundred Years War. But astronomers think the materialmaterial has probably slowed down since the explosion and that its light has therefore reached us a little more recently.

The hypothesis seems confirmed by the observation of the brightest regions in X-rays, where the slowest moving material is located. Even though no X emission is associated with the fastest moving material. Part of the shock wave must therefore have crashed into a gasgas dense surrounding the supernova, effectively causing it to slow down.