The star shown in this Hubble image isn’t very bright. It can’t be seen with the naked eye. Yet, it is our Sun’s closest stellar neighbor. Proxima Centauri, in the constellation of Centaurus (The Centaur), is just over four light-years from Earth. It is quite small compared to other stars, only about an eighth of the mass of the Sun.
Its average luminosity is very low, but, on occasion, its brightness increases. It is what is known as a “flare star,” prone to random and dramatic changes in brightness. Convection processes in the star’s interior not only trigger brilliant bursts of stellar output, but that stirring, combined with other factors, means that Proxima Centauri has a rather extended life expectancy. Astronomers predict that this star will remain middle-aged—what’s known as a “main sequence” star—for another four trillion years. That’s roughly 300 times the age of the current Universe.
Image Credit: NASA / ESA