Proxima Centauri b

Proxima Centauri b (also called Proxima b) is an exoplanet orbiting within the habitable zone of the red dwarf star Proxima Centauri, the closest star to the Sun. It is located about 4.2 light-years (1.3 parsecs, 40 trillion km, or 25 trillion miles) from Earth in the constellation of Centaurus, making it the closest known exoplanet to the Solar System. Upon its discovery, it brought attention for being a possible candidate to habitability. Although current data shows it is not among the best candidates compared to other planets around its size, more information about the planet's physical characteristics is needed for a proper evaluation.

In August 2016, the European Southern Observatory announced the discovery of the planet. Researchers think that its proximity to Earth offers an opportunity for possible robotic exploration of the planet with the Starshot project for, at least, "in the coming centuries".

The planet was found using the radial velocity method, where periodic Doppler shifts of spectral lines of the host star suggest an orbiting object. From these readings, the radial velocity of the parent star relative to the Earth is varying with an amplitude of about 2 metres (6.6 ft) per second.