What is Alpha Centauri, Exactly?
Is it a galaxy, a star, a planet, a soccer team or what?
If you’ve been reading up on space technologies, you may have heard the name Alpha Centauri before. Here, I will give you a short summary of the basic facts about the star system, just enough so you go from not knowing what you are talking about to sort of not knowing what you are talking about. I will also touch on what this all means.
It is the closest star and star system to the earth and contains three stars (wow). Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. Alpha Centauri A and Alpha Centauri B are a binary pair. This means that they orbit a common mass, or in this case, each other. These two stars are 4.3 light-years away from earth.
Proxima Centauri, the third star, is actually the closest to earth and forms the third star in the system. 4.22 light-years away, it is the closest star to Earth besides our sun.
Before going into some deets, here are some definitions:
Main-sequence stars: Ordinary stars that fuse hydrogen in its core using nuclear fusion and has a stable outward pressure.
Luminosity class (labeled with Roman numerals I-V): I are supergiant stars, II are bright giants, III are ordinary giants, IV are subgiants, and V are ordinary main-sequence stars.
Morgan-Keenan system: Temperature, (O, B, A, F, G, K, and M), O being the hot end of the spectrum, then subdivided into a spectrum of 0–9, 0 being the coolest and 9 being the hottest.
Alpha Centauri A
Alpha Centauri A is also known as Rigil Kentaurus, is a primary of the binary system (A and B). It is a hydrogen-burning star with a yellowish color, whose stellar classification is spectral type G2 V (meaning its the second hottest section of the yellow G category and luminosity class V) and is slightly larger and is brighter than the Sun. The mass is about 1.1 times the sun, as well as a surface temperature of 5,790 K, about 9963 degrees Fahrenheit.
Alpha Centauri B
Alpha Centauri B is also known as Toliman, is the second star of the binary star system. It is also a hydrogen-burning star of spectral type K1 V, giving it a more orange color than Alpha Centauri A. It has around 90 percent of the mass of the Sun and a 14 percent smaller diameter. It is cooler with a temperature of 5,260 K, about 9008 degrees Fahrenheit.
Proxima Centauri (C)
Proxima Centauri, the closer one, has two planets and is a red dwarf star. They are Proxima B and Proxima C. Proxima B, discovered in 2016 is in the habitable zone. This is the nearest habitable exo-planet. Proxima C is extremely cold, about 7 times the size of earth. It was discovered in 2019.
What does this mean?
Proxima Centauri is the closest star with exo-planets. So would this be our first step to getting humans to habitable exoplanets? With current technologies (RP1, Hydrogen, methane, etc) would take tens of thousands of years to reach Proxima Centauri. But with new coming techs, we could get there faster than ever. Proxima B is our best shot at another exo-planet to move to, but it is so far, that we have no way of knowing if it even has an atmosphere! Hopefully, in the future, we will be able to figure out ways propelling probes to go much faster and be able to check out our nearest neighbor.
Here’s a more in-depth video for more information. Bear in mind that this was made before the discovery of Proxima c in 2019.
