Tuesday, September 20, 2022

DETERMINE THE AGE OF A SUPERNOVA REMNANT

SNR 0519 is the remnant of a white dwarf that blew up after exceeding its critical mass limit. There are several mechanisms through which a white dwarf accumulates mass, such as a collision with another white dwarf or a mass transfer from a companion star into a binary system. Whatever the process, the end result is the explosion and destruction of the white dwarf.
One of the most complex aspects to determine of the remains of supernovae is their age. New observations from the Hubble and Chandra telescopes allowed us to pinpoint when SNR 0519 should have formed. This is a supernova remnant located within the Great Magellanic Cloud, 160,000 light-years from Earth.
The nebula was observed by Hubble in 2010, 2011, and 2020. New observations, coupled with the X-ray data obtained by Chandra, have made it possible to follow the evolution of its dimensions over the years. From the analysis of the data a gas expansion rate of approximately 9 million km per hour was obtained. Assuming that this velocity has remained constant over time and given the current size of the nebula, it has been established that the light from the explosion should have reached Earth 670 years ago.
More realistically, the gases have slowed down their expansion over time and the age thus obtained is only an upper limit of the real value. It is therefore highly probable that supernova light has reached Earth more recently than 670 years ago. 
Credit: X-ray: NASA/CXC/GSFC/B. J. Williams et al.; Optical: NASA/ESA/STScI.

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