Astronomers turn back the clock to determine the timeline of a stellar explosion

While astronomers have seen the debris from numerous exploded stars in the Milky Way and nearby galaxies, pinpointing the time frame of the star’s demise is often difficult. By studying the spectacular remnant of a supernova in a neighboring galaxy with NASA telescopes, a team of astronomers has found enough clues to turn back the clock.

The supernova remnant called SNR 0519-69.0 (SNR 0519 for short) is the debris from a white dwarf star explosion. After reaching critical mass, either by stripping matter from a companion star or merging with another white dwarf, the star underwent a thermonuclear explosion and was destroyed. Scientists use this type of supernova, called Type Ia, for a variety of scientific studies ranging from studying thermonuclear explosions to measuring distances to galaxies billions of light-years across.

SNR 0519 is found in the Large Magellanic Cloud, a small galaxy 160,000 light-years from Earth. This composite image shows X-ray data from NASA’s Chandra X-ray Observatory and optical data from NASA’s Hubble Space Telescope. Low, medium, and high energy X-rays from SNR 0519 are shown as green, blue, and violet, respectively, with some of these colors overlapping to appear white. Optical data shows the perimeter of the remnant in red and stars around the remnant in white.

Astronomers combined the data from Chandra and Hubble with data from NASA’s decommissioned Spitzer Space Telescope to determine how long it has been since the star in SNR 0519 exploded and to learn more about the environment in which it is located the supernova happened. This data gives scientists the ability to “rewind” the film. the stellar evolution that has unfolded since then and find out when it began.

The researchers compared Hubble images from 2010, 2011 and 2020 to measure material velocities in the blast’s blast wave, which ranged from about 3.8 million to 5.5 million miles (9 million kilometers) per hour. If the speed was at the higher end of these estimated speeds, astronomers determined that the light from the explosion would have reached Earth about 670 years ago, or during the Hundred Years’ War between England and France and the height of the Ming Dynasty in China.

However, it is likely that material has slowed since the initial explosion and that the explosion occurred more recently than 670 years ago. Chandra and Spitzer’s data provide evidence that this is the case. Astronomers found that the brightest regions in X-rays of the remnant are where the slowest-moving material resides, and that no X-ray emission is associated with the fastest-moving material.

These results imply that part of the blast slammed into dense gas around the remnant, slowing it in its path. Astronomers can use additional Hubble observations to more accurately determine when the star’s demise should really be timed.

An article describing these findings was published in the August issue of The Astrophysical Journaland a preprint is available online.