Proxima Centauri

The star

Proxima Centauri was first discovered in 1915 and is the nearest known star to our Sun. Proxima Centauri is a member of the Alpha Centauri System, a triple star system from Alpha Centauri A, Alpha Centauri B and Proxima Centauri. Proxima Centauri has three exoplanets orbiting it, namely Proxima Centauri B, C and D.

Proxima Centauri B

Proxima Centauri B orbits it's system's star within the habitable zone, making it the closest potentially habitable planet from Earth with a distance of just about 4 light years. Although it's atmosphere and surface properties are not certainly determined yet, it is thought to be an earth-like planet with a mass and radius very similar to Earth. Proxima Centauri B is, similarly to planets from the Trappist System, possibly tidally locked, however scientists aren't entirely agreeing on this topic yet.

Due to the close proximity of Proxima Centauri B and the lack of information we have about it, a robotic space exploration mission named Breakthrough Starshot (opens in a new tab) is planned to target the system and send light-sail powered nano probes named Starchips into the planet's orbit. The goal of the mission that was founded by venture capitalist Yuri Milner, Stephen Hawking and Mark Zuckerberg was to collect enough information about the Alpha Centauri system to launch manned missions to it someday in the future.

Proxima Centauri C

Proxima Centauri C was just recently discovered when the team under italian astrophysicist Mario Damasso noticed subtle movements from Proxima Centauri, indicating a second big planet orbiting Proxima Centauri. It's discovery has just recently been made publicly in 2020.

Proxima Centauri C is thought to be a Super-Earth, a type of exoplanet with a mass much higher than Earth's but smaller than that of ice giants like Uranus and Neptune. Due to it's high distance to it's star and the resulting low equilibrium temperature of around −234 °C sadly make it uninhabitable.

Proxima Centauri D

Proxima Centauri D is a small exoplanet orbiting close around it's star with around one quarter the mass of Earth. Due to it's close proximity to Proxima Centauri it receives around 190% of Earth's irridation and reaches an equilibrium temperature of around 87 °C.

Summary

Due to Proxima Centauri C being too cold and Proxima Centauri D being too hot, only Proxima Centauri B remains as a possible colonization target for our future missions outside of the solar system. That isn't too bad considering Proxima Centauri B orbits it's star right inside the habitable zone. Due to the fact it not only has almost the same size but also the same mass as Earth, chances are it's composition is similar to Earth, meaning it might have liquid water.

Of all the exploration we will undergo outside of our solar system, Proxima Centauri B is extremely likely to be our very first target for human missions. As you can see, we have every reason to be excited about findings from the Breakthrough Starshot (opens in a new tab) mission.

Additional Resources

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You can find more information and possibly future updates from it on the official website of the Breakthrough Starshot mission.