The second-closest star to the Sun, 5.9 l.y. away in Ophiuchus. It is an M4 dwarf of apparent magnitude 9.5, with a luminosity 2000 times less than the Sun’s. It has the largest proper motion of any star known, 10″.36 per year, as was discovered in 1916 by E. E. Barnard, after whom the star is named. It is a variable of BY Draconis type, fluctuating by a few hundredths of a magnitude, and is also known as V2500 Ophiuchi.