I am collecting facts for an story featuring the end of the world. In this Story Betelgeuse is the culprit. I know currently its poles are not lined up with Earth so I need to describe an event that would alter its position so that when it goes, Earth is in the line of fire. Would a black hole passing near Betelgeuse work? Would such an event be difficult for Astronomers to detect until it was too late? If the poles were aligned with Earth and the start went off , when Earth was hit with the radiation burst, how long would it take to sterilize the planet and how long would it take for vegetation and animal life to recover? thanks for the help.