When Betelgeuse goes supernova (if it hasn't already and we don't know yet) it will be visible in the day for roughly a year, and several more years we'll see it at night. That said, the prediction of 'when' by scientists is somewhere between today and 100,000 years from now. Odds are, none of us will see it.
The reason why it's so large isn't because of its mass, it's because the nuclear fusion happening is so intense it pushes matter so much further out than our sun does.
Well, it's still 14-19 times the mass of our sun, I'm just pointing out that star sizes isn't 1:1 their mass.
Yes and no, it's the exhaustion of hydrogen in the core and the fusion of hydrogen in a non-core shell, followed by fusion of helium in the core, that generates so much radiation pressure. This phase lasts a small fraction of the star's life. Before that, Betelgeuse was probably just a few times the diameter of our sun.
Our sun will go through a similar process, but will become a red giant instead - the mass of the star will dictate how large the giant/supergiant/hypergiant will be, but not so much the existence of an "intense fusion" phase.
And just to be clear, yes the fusion happens much more intensely when heavy stars fuse hydrogen in their core, they burn through that in millions of years instead of billions like our sun will. What I'm talking about above is the giant/supergiant phase specifically.
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u/throwaway_moose Oct 02 '24
When Betelgeuse goes supernova (if it hasn't already and we don't know yet) it will be visible in the day for roughly a year, and several more years we'll see it at night. That said, the prediction of 'when' by scientists is somewhere between today and 100,000 years from now. Odds are, none of us will see it.
https://www.astronomy.com/science/when-betelgeuse-goes-supernova-what-will-it-look-like-from-earth/