A binary star system, consisting of two red
dwarfs, that lies only 11.5 light-years away in the northeast part of
Draco (R.A. 18h 42.8m, Dec. +59° 37.8'),
northeast of Xi Draconis and southwest of Delta Dra. Both stars show some
variability; Struve 2398 A (spectral type M3.0, luminosity 0.00027 Lsun,
mass 0.36 Msun, radius 0.54 Rsun) has been given the
New Suspected Variable designation of NSV 11288, while Struve 2398 B (spectral
type M3.5, luminosity 0.00013 Lsun, mass 0.30 Msun,
radius 0.55 Rsun) is a flare star.
The system's orbit has a period of some 408 years with an eccentricity of
0.53, giving an average separation between the stars of 56 AU, and a range
of 26–86 AU.
Photo: ESO Online Digitized Sky Survey