The closest known exoplanet to Earth, Proxima b, could have the required conditions for liquid water and even life. That’s according to a new study that used a novel method to study conditions on this world.
Announced in August 2016, Proxima b is about 4.2 light-years from Earth in orbit around our closest star, Proxima Centauri. We believe it is a rocky world and, being so close to us, presents a fascinating opportunity for further examination.
This latest study, published in Astronomy and Astrophysics, was led by the University of Exeter. They applied a model from the Met Office in the UK, normally used to investigate Earth’s climate, to simulate conditions on Proxima b.
“With the right atmosphere, this planet is potentially habitable,” Dr Nathan Mayne, one of the co-authors on the paper, told IFLScience.
The model is called the Met Office Unified Model. Plugging values into a supercomputer at the University of Exeter over several months, they were able to work out the possibilities of Proxima b having liquid water.
At the moment, we don’t know a huge amount about the planet. We know its mass is at least 1.27 times that of Earth, with a radius of at least 1.1 times our planet's. It’s thought to orbit its star in about 11 Earth days, at a distance of just 5 percent Earth’s orbit around the Sun, but within its star's habitable zone.
Its star poses some intriguing problems, being an M-type red dwarf. There has been much speculation of late as to how habitable planets around these stars will be, as while they are dimmer and cooler than those like our Sun, they are prone to extreme flaring events.
Nonetheless, this latest study argues that there is a good chance Proxima b could be habitable. The biggest factor will be how eccentric its orbit around the star is. If it’s between 0.1 and 0.35 – with 0 being a circle and 1 being a parabola with no end – all signs point to the planet being able to host liquid water and having moderate temperatures suitable for life.