Betelgeuse is a red supergiant that is very unstable, and is expected to supernova in a hundred thousand years. It is colder than the Sun and has begun to fuse helium instead of hydrogen. If you replaced the Sun with Betelgeuse, it would engulf at least all planets up to Mars, and possibly Jupiter and all the Asteroids in the Asteroid Belt.
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When Betelgeuse supernovas, the radiation will not reach Earth because it is many Light-years away, and if any does, it will be blocked by Earth’s magnetic field. Some people say that the supernova will be as bright as the full Moon in the sky.