The fifth closest star to Earth is a red dwarf star currently located about six light years away (it is headed towards us so the distance changes).  It is named Barnard’s Star after the American astronomer E. E. Barnard who discovered it in 1916.  Sometimes it is called Barnard’s Runaway Star because it has the greatest proper motion of any star (proper motion is how much a star seems to move across the sky as seen from earth).

Barnard's Star Rockets through the heavens in this dramatic video

Barnard’s star has 17% of the Sun’s mass and is very dim.  It is invisible to the naked eye and must be viewed with a telescope.  The star has a very low metallicity which indicates that it is a Population II star.  Stars are roughly classed into three groups by age:

Population I: comparatively recent stars such as the sun

Population II: ancient low-metal stars formed after the first generation of stars had died but before the universe had great quantities of material heavier than simple gasses

Population III: the oldest stars which were metal free and believed to have all died in the universe’s infancy

Astronomers do not know how to clearly ascertain the age of a red dwarf so all that we can say for certain is that the star is between 7 and 12 billion years old.

Artist's Conception of Barnard's Star from a Planet which Probably Doesn't Exist

In the sixties an astronomy professor claimed to have discovered a Jupiter-sized planet orbiting Barnard’s Star, but more sophisticated readings taken with the Hubble Space Telescope have made this seem unlikely.  During the seventies and eighties Barnard’s Star was proposed as a destination for an interstellar space voyage known as Project Daedalus.  Interest in this idea has waned since the discovery that Barnard’s star is bereft of planets.  Additionally humankind has progressed more slowly than anticipated and the technology for such a mission still does not exist.

The Daedalus Starship Blasts Off from the Solar System Heading for Barnard's Star: Don't Look for This Anytime Soon