Friday, July 2, 2021

This is Proxima Centauri

Proxima Centauri is a red dwarf located just 4.23 light years away from Earth, making it the closest star to the Solar System. Despite this Proxima Centauri is far too faint to be seen with the naked eye: its apparent magnitude is in fact +11.

The star was discovered in 1915 by Robert Innes from photographic plates obtained from the Cape of Good Hope Observatory in South Africa. The astronomer analyzing the proper motion of the star realized that it belonged to the Alpha Centauri system, while studying its parallax showed that it was the closest star to the Sun.

In the following years it was realized that Proxima Centauri is a flare star: this category includes all the red dwarfs that are subject to sudden and irregular increases in brightness with a maximum duration of a few hours. These variations are caused by flares due to the star's magnetic activity.

Being located so close to Earth, the characteristics of Proxima Centauri are known with great precision: its mass and diameter are respectively one eighth and one seventh of those of the Sun.

Having managed to accurately determine its composition, it was possible to calculate how long Proxima Centauri will remain a main sequence star. Well the star will continue to live for another 4000 billion years, more than 300 times the current age of the Universe!

Credit: NASA, ESA, Hubble.

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