JWST Captures Image of Supernova That 'Absolutely Shattered' a Star
smithsonianmag.com
smithsonianmag.com
Not sure if anyone is relaying it over the Internet, but I looked it up, and the remnants will last for at the very least hundreds of years:
> The expanding cloud of material left over from the supernova now appears approximately 10 light-years (3 pc) across from Earth's perspective
Would love for an astrophysicist to pine in. But my understanding is supernovae are usually balanced enough to squeeze their stars' cores. This appears to have been unbalanced such that the core was "broken" instead of uniformly compressed.
[1] https://en.wikipedia.org/wiki/Zombie_star
[2] https://iopscience.iop.org/article/10.3847/1538-4357/ac3bbd/...
Is this noteworthy because we’ve seen it, rather than that it exists? How many novae cores have we imaged before?
These are some of the first images we’ve probably inside the after effects due to the nature of the scope.
The others usually retain their core, either as a neutron star or the final collapse to a black hole.
> There are also several light echoes visible in this image, most notably in the bottom right corner. This is where light from the star’s long-ago explosion has reached, and is warming distant dust, which is glowing as it cools down.
Or, to put it another way, could we detect the damaging effects of a nearby supernova expanding towards us before those effects actually hit us? And if so, by what factor?
https://news.fnal.gov/2019/03/waiting-for-neutrinos/
https://earthsky.org/astronomy-essentials/safe-distance-from...
Huh? Presumably the electromagnetic radiation travels at the speed of light, and neutrinos travel more slowly; so the neutrinos arrive after the dangerous rays, not before.
https://en.wikipedia.org/wiki/Measurements_of_neutrino_speed
Since the light emitted from the inner core during the supernova is instantly absorbed by the matter collapsing inward, it must be re-emitted and re-absorbed many times before it can reach open space and begin its journey to earth. With such an incredibly high density in the core of the collapsing star, the mean free path [1] of the light is extremely short, so this process can take a very long time.
So the early arrival of the neutrinos is entirely the result of EM radiation being absorbed within the star and re-emitted, while the neutrinos can pass straight through. I wondered if that was the explanation.
They say the supernova happened 350 years ago; and that "Baby Cas A" is 170 light-years behind Cas A. So the echo "caught up" with light coming our way about 340 years ago; that is, the echo consists of light that was emitted just 10 years after the explosion.
Have I got that right?
[Edit] The "echo" isn't really a reflection; it's emission from a gas-cloud heated by the original explosion, as it cools down. So it's not really reflected light from the original event.
https://jwst-docs.stsci.edu/getting-started-with-jwst-data seems like a good spot to start.
Perhaps the story could have Cylons in it, but here they're allies with the humans, but after the supernova, some religious leader convinces most of them that their god wants them to destroy the humans.
I think, ball park, a SN 500 light years out is considered safe e.g. Betelgeuse. Our Milky Way galaxy is thought to be roughly 100,000 light years in diameter so we should be safe from all but those within about a hundredth of the radius of our galaxy from us.
space is big ...
It wouldn't wipe out the solar system, but might have harmful impacts on our biosphere.
We can take some comfort in the fact that we’d never know it happened, and theorists have asserted that it’s highly unlikely a false vacuum of any size could exist for more than a moment in the presence of gravitational forces, plus physics within the bubble would be “super weird”, I think is the technical term.
https://en.m.wikipedia.org/wiki/False_vacuum#Existential_thr...
Can anyone explain the above phrase?
I'm not an expert, but an analogy here could perhaps be if you drop a cup of water on the floor (assuming it doesn't break) some of that water is going to rebound on itself/the cup, and will splash upwards. That would be gravitational potential energy being converted to kinetic energy, causing material to be ejected.
With stars, there is a TON of gravitational potential energy, and so when it's converted to kinetic energy during a collapse, you "explode" the lighter weight outer layers of the star away from the more dense core. Some of the stars core remains, and can become either a neutron star or a black hole.
Just to be sure I understand, the event horizon of the new black hole would have to lie within the interior of the original star, right?
This is usually balanced and you have a nice star. When the fusion slows as the star exhausts fuel, gravitational pull dominates and everything falls inward in a collapse. That presses the inner bits together nice and tight, and then the outer bits bounce off it.
So you have a collapse inward with an explosion as everything bounces off. Wikipedia has a nice picture.
<https://archive.org/details/collapsinguniver0000asim>
Stars are a contest between gravity and the nuclear strong force, with stellar fusion creating the heat and pressure required to resist, at least for a time, the pull of gravity. The larger a star, the faster it burns through its hydrogen fuel. While brown dwarf stars may have liftimes in the trillions of years, our Sun will expend all its fuel in about 11-12 billion years (it's about half-way through that process now), and will gradually grow hotter and brighter as it does so (it's already about 25% brighter than it was when the Earth was formed). The largest stars have lifespans of only a few million years, roughly dating to when the proto-hominids diverged from their last common ancestor with chimpanzees, and far more recently than the dinosaurs died out.
It's a useful lesson to recall that bigger and more energy-hungry does not necessarily mean longer-lived, and quite often means precisely the opposite.
<http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/startime.ht...>
Mind went supernova