If something catastrophic were to happen to Earth and our Sun, finding another star or planet for humans to live on would be an immense challenge. The distances between stars are vast, and the conditions required for human habitation are very specific.
Currently, there are no known exoplanets (planets outside our solar system) that have been identified as suitable for human habitation. The search for potentially habitable exoplanets is an active field of scientific research, but the technology and understanding needed to identify and assess such planets are still developing.
In the event of a hypothetical scenario where humans needed to find a new celestial body for habitation, some potential options could include:
Proxima Centauri: The closest star system to our Sun, located about 4.24 light-years away, has a small rocky exoplanet called Proxima Centauri b. It lies within the star's habitable zone, but many details about its composition and potential habitability are still uncertain.
TRAPPIST-1 System: This star system is about 39 light-years away and hosts seven known Earth-sized planets, three of which are in the habitable zone. They are called TRAPPIST-1b, TRAPPIST-1c, and TRAPPIST-1d. However, further studies are required to determine their potential for habitability.
It's important to note that even if potentially habitable exoplanets are discovered, the challenges of interstellar travel, establishing sustainable ecosystems, and adapting to a different planetary environment would be immense. At present, Earth remains the only known planet where human life can be sustained naturally.