Our Closest Stellar Neighbor

If I am going to be honest, my decision to dedicate this blog post to the Alpha Centauri system comes from a TV show that I watched a few years ago. Netflix’s remake of Lost in Space follows a family as they travel across the universe to Alpha Centauri to start a colony there. Captured by the idea of a habitable planet other than Earth, my fascination with exoplanets can be attributed to this show. If you have not yet seen it, I highly recommend giving it a watch!

In the vast expanse of outer space, it is a miracle that we have the technology to discover stars and planets that are trillions of miles away. Located 23.5 trillion miles away, the Alpha Centauri System is the closest star system to our solar system. It is comprised of three stars, two of which are gravitationally locked in a binary system: Alpha Centauri A (Rigil Kentaraus) and Alpha Centauri B (Toliman).Yes, it is confusing: the entire star system is referred to as Alpha Centauri as well as the individual stars. To ease this confusion, I will refer to these stars by the names in the parentheses. Rigil Kentaraus is slightly more massive than our sun and 1.5 times brighter (EarthSky)!

Photo: obtained from Space.com

The real fascination with the Alpha Centauri star system comes from the third star, Alpha Centauri C (Proxima Centauri). Out of all three stars, Proxima Centauri is the closest to Earth at 4.2 light years away. Unlike our Sun which will begin to die in 5 billion years, Proxima Centauri still has another 4 trillion years left. Even more remarkable, three planets have been detected to orbit it. Of these three, Proxima Centauri b is the most fascinating because it lies within Proxima Centauri’s habitable zone. Since Proxima Centauri is a red dwarf star and gives off much less energy than our Sun, its habitable zone spans much closer to the star than ours. Therefore, even though Proxima Centauri b is “at a distance about 5% of the distance between Earth and the sun”, it is sill within the habitable zone (Space.com).

Image: obtained from Space.com

Could life thrive on Proxima Centauri b?

Although the exoplanet is located in a region where liquid water seems possible, the planet itself may seem less hospitable. According to Universe Today, it seems that the chaotic nature of red dwarf stars like Proxima Centauri, coupled with the short distance between it and its exoplanet, Proxima Centauri b, may leave a world that receives 1000 times more solar wind radiation than Earth. Further, even though Alpha Centauri is the closest system to Earth, at speeds of 17,500 mph, it would still take more than 148,000 years to travel there (Space.com). Even if Proxima Centauri b may not be as hospitable as we had initially thought, and that we cannot reach Alpha Centauri with our current technology, studying this system reveals that our planet Earth may not be the only planet with the potential for life!