5 ms·
For those curious, this supernova is unfortunately too old to find the supernova remnant that was left behind. The most famous SNRs are Cas A [1] and M1/the Cra
by autocorr 10y ago
For those curious, this supernova is unfortunately too old to find the supernova remnant that was left behind. The most famous SNRs are Cas A [1] and M1/the Crab Nebula [2].
When the core of a massive star collapses, the resulting explosion launches the rest of the star surrounding the core outwards. Near to the star, this explosion proceeds as an unimpeded free expansion for a few hundred years, but the ejecta eventually impacts the gas between the stars, the interstellar medium. The ejecta then goes through two phases, an adiabatic phase (ie can't efficiently radiate away the heat) and radiative phase (ie can efficiently radiate away the heat). The adiabatic phase ends after around a couple ten thousand years, and the radiative phase ends after a few hundred thousand. As the remnant evolves, the gas becomes cooler and less dense, until eventually it's indistinguishable from the rest of the interstellar medium. So, if this supernova occurred around 2 million years ago, we shouldn't be able to observe the remnant. A shame!
[1] https://apod.nasa.gov/apod/ap050615.html https://apod.nasa.gov/apod/ap050615.html
[2] https://apod.nasa.gov/apod/ap150816.html https://apod.nasa.gov/apod/ap150816.html
- robbiep 10y agoI understand it is possible to observe reflections of large supernova level events. A possibility?
- lawless123 10y agoOur Galaxy is 100K light years across, the light would already have dissipated.
- planteen 10y agoI didn't know about this. Googled and found the Wikipedia about light echoes. Very neat. https://en.wikipedia.org/wiki/Light_echo https://en.wikipedia.org/wiki/Light_echo
- jcims 10y agoSeems like black holes could have this same effect on light from supernovas due to gravitational lensing. In fact, there should be some part of the area around a black hole in which the lensing effect bends light 180 degrees. With a big enough telescope we could observe our own solar system as it was thousands of years ago.
- deleted 10y ago[deleted]
- sixbrx 10y agoJust to add one thing because it's neato: the core collapses the moment when the star begins doing fusion on iron, which is the first fusion in the chain of successive fusions to absorb energy instead of produce it.
- arethuza 10y agoThis process is weaponized in the novel Iron Sunrise by Charlie Stross. https://en.wikipedia.org/wiki/Iron_Sunrise https://en.wikipedia.org/wiki/Iron_Sunrise