Shining brightly in this space wallpaper by the Hubble Space Telescope is our closest stellar neighbor: Proxima Centauri. Proxima Centauri lies in the constellation of Centaurus (the Centaur), just over four light-years from Earth. Although it looks bright through the eye of Hubble, as you might expect from the nearest star to the solar system, Proxima Centauri is not visible to the naked eye. Its average luminosity is very low, and it is quite small compared to other stars, at only about an eighth of the mass of the Sun. However, on occasion, its brightness increases. Proxima is what is known as a "flare star," meaning that convection processes within the star's body make it prone to random and dramatic changes in brightness. This image was released Nov. 1, 2013.