Struve 2398

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**Struve 2398 A/B**
Observation data Epoch J2000
Struve 2398 A/B
Constellation (pronunciation)	Draco
Right ascension	18^h 42^m 46.7/46.9^s
Declination	+59° 37′ 49/36″
Apparent magnitude (V)	8.94/9.70
Characteristics
Spectral type	M3 V/M3.5 V
U-B color index	1.11/1.14
B-V color index	1.53/1.59
Variable type	Flare star
Astrometry
Radial velocity (R_v)	-0.9 km/s
Proper motion (μ)	RA: -1327 mas/yr Dec.: 1802 mas/yr
Absolute magnitude (M_V)	11.20/11.96
Details
Mass	0.36 / 0.30 M_☉
Radius	0.54 / 0.55 R_☉
Luminosity	0.00027 / 0.00013 L_☉
Temperature	2.000–3.500 K
Metallicity	?
Rotation	?
Age	? years
Visual binary orbit
Companion	Struve 2398 B
Period (P)	408 yr
Semimajor axis (a)	12.1"
Eccentricity (e)	0.53
Inclination (i)	356°
Database references
SIMBAD	data
Other designations
Σ 2398 A/B, HD 173739/173740, GCTP 4330.00 A/B, LHS 58/59, GJ 725 A/B, Gl 227-046/227-047, HIP 91768/91772, A: BD +59°1915, Vyssotsky 184.
Database references
SIMBAD	data

Struve 2398 is a binary star system in the constellation Draco. Both stars are red dwarfs and both display variability common to flare stars. The orbital period for the pair is about 408 years, with an average distance of about 56 astronomical units, and the eccentricity of the orbit is 0.53.