One of the intrinsically faintest stars known; also designated VB 10 and V1298 Aql. It is an M8 dwarf less than 1/350 000 as luminous as the Sun (absolute magnitude 18.7), 19.2 l.y. away in Aquila; visually it appears of magnitude 17.3, although subject to variations of a few tenths of a magnitude as it is a flare star of UV Ceti type. It is a companion to another red dwarf, BD +4° 4048, and is named after its discoverer, the Belgian astronomer Georges Achille Van Biesbroeck (1880–1974).