Hubble telescope captures portrait of sun's closest neighbor star

BALTIMORE, Nov. 1 (UPI) -- NASA has released a Hubble space telescope photo of Proxima Centauri, the star closest to the sun that, despite being so close. is not visible to the human eye.

Just over 4 light-years from Earth, in the constellation of Centaurus, Proxima Centauri cannot be spotted in the night sky by human skywatchers because its average luminosity is very low, and it is quite small compared to other stars, at only about 1/8 the mass of the sun, NASA said Friday.

The new image, released by the Space Telescope Science Institute in Baltimore, was captured with Hubble's Wide Field and Planetary Camera 2 (WFPC2).

Proxima Centauri is part of a triple star system, with two companions, Alpha Centauri A and B.

Its brightness increases on occasion, making it what is known as a flare star, where convection processes within the star's body make it prone to random and dramatic changes in brightness.

Proxima Centauri will be a very long-lived star, astronomers said, predicting it will remain middle-aged -- or a "main sequence" star in astronomical terms -- for another 4 trillion years, 300 times the current age of the universe.