Our second nearest star, the sun being the closest, is a little over 4 light years away or more than 24 trillion miles. It is located in the constellation Centaurus, the Centaur.
Although very bright in this picture taken by Hubble Space Telescope, Proxima Centauri is not visible to the naked eye. It is very small compared to other stars, only about an eighth of the mass of the sun, but with a density 40 times greater than our Sun. It is relatively cool compared with much larger stars and, in theory, will burn for trillions of years before spending all its fuel.
Proxima is a red dwarf star. Red dwarfs are very common in our neighborhood, making up nearly 3/4 of the stars in the Milky Way.
While its average luminosity is very low, Proxima Centauri is also known as a flare star. The star's magnetic field is responsible for creating occasional flashes of brilliant light. The convective activity within the body of the star is responsible for creating its magnetic field. The convection process of mixing fuel at the core of the star maintains a consistent low energy production rate which means the star be middle-aged or what astronomers call a main sequence star for a very long time, approximately 4 trillion years, some 300 times the age of the universe. To put that in perspective, the universe is roughly 14 billion years old.