The dazzling protagonist of this Hubble image is the star closest to us: Proxima Centauri.
Proxima Centauri is located in the constellation Centaurus (the Centaur), just over four light-years from Earth. Although it looks bright to Hubble’s eyes, as you might expect from the nearest star to the Solar System, Proxima Centauri is not visible to the naked eye. This is because its average luminosity is very low and its size is very small compared to other stars, with a mass that is one-eighth that of the Sun.
However, sometimes its brightness increases. Proxima is what is known as a “bright star”, because the convection processes inside it tend to cause unpredictable and spectacular changes in its brightness. These processes not only cause glowing bursts of light, but in combination with other factors make Proxima Centauri look forward to a long future. Astronomers predict that this star will retain its middle age – or “main sequence” in astronomical terms – for another four billion years, about three hundred times the age of the current universe.
These observations were made with Hubble’s Wide Field and Planetary Camera 2 (WFPC2). Proxima Centauri is part of a three-star system, but its two companion stars, Alpha Centauri A and B, are outside the image frame.
Although, in cosmic terms, it is a nearby star, Proxima Centauri barely looks like a dot even to Hubble’s keen eye, accounting for the vast scale of the universe around us.