why is the Crab Nebula visible?

Factual Questions
1

If the crab nebula is the remnant of a supernova star, why is it that after 1000 years we can still see it? A star explodes… ok sure. But why is the residue of a star glowing afterwards? and visible from thousands of light years away? A star is visible because of nuclear fusion. What makes the diffuse gas of an exploded star glow?

2

IIRC, there’s still a neutron star formed as a result of the supernova. That should be enough to ionize the gases. The nebula gases alone won’t account for all the mass of the supernova. The vast bulk is still where the original star was.

3

The central pulsar (the neutron star remnant of the original stellar core) pumps energy into the surrounding nebula.

4

At its core is a rapidly rotating neutron star - a pulsar - that is a powerful source of radiation emitting a wide range of frequencies and a total energy at least 10,000 times that of our sun. This is what continues to illuminate the expanding remnants of the supernova the created the Crab Nebula nearly 1000 years ago.

5

Not one but two ninjas that time…

6

Nebula neutron ninjas …

7

Got it. thanks.

8

Note that neutron stars are no longer burning any fuel, and so they will eventually fade out with time. That time just hasn’t come yet for the Crab Pulsar, which is still quite young.

9

So the Crab Nebula… is the galaxy’s biggest CFL? :slight_smile:

10

The same basic principle that makes Vegas so bright. No, not Vega, Vegas. Energy input into a gas ionizes it and makes it give off light. In the case of the Crab Nebula, because the source is highly energetic, a lot of that light isn’t visible - the Crab is one of the biggest X- and Gamma ray sources in the sky.

11

That pulsar is rather impressive. It’s around 20 km in diameter, has a mass around 1.4 times that of our sun, and rotates at 1800 rpm. Some sources say its total luminosity may be 75,000 times that of the sun.

12

:confused: “CFL” ?

ETA: please use the word “plerion” in future discussions of the nebula per se. Because it’s Greek and all, but different.

13

CFL

Plerion

Everything I know I learned through Google…

14

All of that is fairly typical of pulsars, actually, and there are some that are much more extreme.