A black hole with the Sun's mass would have an event horizon of just 2.95 km in radius, small enough to sit inside a town. Mass and spin a* decide the rest: the innermost stable circular orbit shrinks from 3 Rs towards 0.5 Rs for a maximally spinning hole, while the dark shadow keeps an apparent diameter near 5.2 Rs. Around such a hole play out the tidal disruption of a star, mergers, relativistic jet flares and Hawking evaporation.
A black hole with the Sun's mass would have an event horizon of just 2.95 km in radius, small enough to sit inside a town. Mass and spin a* decide the rest: the innermost stable circular orbit shrinks from 3 Rs towards 0.5 Rs for a maximally spinning hole, while the dark shadow keeps an apparent diameter near 5.2 Rs. Around such a hole play out the tidal disruption of a star, mergers, relativistic jet flares and Hawking evaporation.
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