The planet Proxima b was discovered earlier this year. It orbits a star called Proxima Centauri just 1.3 parsecs from the Sun, and has a mass at least 30% greater than Earth’s. Ignasi Ribas at the Institute of Space Sciences in Bellaterra, Spain, and his colleagues reconstructed the evolution of the planet to estimate how much water it may have contained over time. Despite being zapped with 30 times as much ultraviolet radiation and 250 times as many X-rays as Earth receives from the Sun, the planet could have retained most of the water from its formation. In some evolutionary scenarios, Proxima b’s atmosphere would have protected it from this onslaught.
A second team led by Martin Turbet at the Laboratory of Dynamic Meteorology in Paris explored the planet’s possible climates. The researchers conclude that it could have many possible gas combinations in an atmosphere that would permit liquid water to exist on its surface today.