Actually, this star is a system of stars, consisting of two sun-like objects and a red dwarf. The latter is located just 4,243 light-years away from the Earth, making it the closest star to the Sun!
Proxima Centauri, this is its name, is as said a red dwarf that moves around the two other components of the system, Alpha and Beta Centauri, on a very eccentric orbit characterized by a periastro of 4300 AU and an apoastro of 13000 AU.
Being so close to Earth the properties of Proxima Centauri are known with great precision. The star has a radius and a mass that are respectively equal to just 14% and 12% of the radius and mass of the Sun, while its surface temperature is just 2900 K.
Being so small and cool Proxima Centauri will take a lot of time to burn all its available nuclear fuel. In fact, it is estimated that the star, despite already having an age of 4.85 billion years, will not stop burning the hydrogen at its disposal, thus remaining along the main sequence, for another 4000 billion years, 300 times the current age of the Universe!
Despite being so close to Terra Proxima Centauri is too weak to be observed with the naked eye. Indeed, with its eleventh apparent magnitude, the star can only be seen by telescopes of more than 10 cm in diameter, under optimum sky conditions.
Curiously, Proxima Centauri is so weak that it can be observed with difficulty also by Alpha and Beta Centauri: from the two main components of the Proxima system it would in fact appear as a star of fifth magnitude, at the limit of visibility to the naked eye.
Credit: NASA, ESA, Hubble.
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