© ESA/Hubble & NASA. Acknowledgement: Claude Cornen
SNR 0519 is located over 150 000 light-years from Earth in the southern constellation of Dorado (The Dolphinfish), a constellation that also contains most of our neighboring galaxy the Large Magellanic Cloud (LMC). Because of this, this region of the sky is full of intriguing and beautiful deep sky objects.
The LMC orbits the Milky Way galaxy as a satellite and is the fourth largest in our group of galaxies, the Local Group. SNR 0519 is not alone in the LMC; the NASA/ESA Hubble Space Telescope also came across a similar bauble a few years ago in SNR B0509-67.5, a supernova of the same type as SNR 0519 with a strikingly similar appearance.
"...The thin, blood-red shells are actually the remnants from when an unstable progenitor star exploded violently as a supernova around 600 years ago..."
"SNR 0519 is located over 150 000 light-years from Earth..."
This makes no sense. If the nebula is over 150,000 lights years from Earth, then we are seeing it as it existed over 150,000 years ago. Light from something that happened 600 years ago would barely be beginning its journey to us.
Perhaps the author means that the supernova occurred 600 years prior to what we see today -- that 600 years ago, the supernova was -- or could have been -- seen on Earth?