What is the closest planet outside of our solar system?

1 Answer
Apr 4, 2018

It would be the exoplanet which is orbiting the star Proxima Centauri.


In August, 2016, astronomers confirmed the discovery of an exoplanet orbiting within the habitable reaches of Proxima Centauri, the closest star to Earth and part of the small star system; Alpha Centauri- a triple star system just over 4 light years away.

Its believed to have a mass of 1.3 of Earth- meaning its gravity would only be slightly more burdening, but means that it is likely to be a rocky planet as well.
It orbits Proxima Centauri every 11.2 (Earth) days, at only 1-tenth of the distance between Mercury and the Sun.

But why is it habitable? This is due to the fact it is a brown dwarf star, meaning it is incredibly small, and also less hot than our Sun, it is also a slowly burning Sun, and finds it incredibly difficult to nuclear burn hydrogen due to its small mass and is what is often known as a 'failed star'.

This discovery however, is not at all a failure, and gives us the best chance of finding life in a star system outside of our own, as well as it being in the peculiar place of a triple star system, and that the two other stars orbit each other (though, this still at some distance from one another).

Hope this helps!
-C. Palmer