26 Aurigae

26 Aurigae is a binary star^[3] system in the northern constellation of Auriga. It is visible to the naked eye as a faint star with an apparent visual magnitude of 5.41.^[2]

26 Aurigae

Observation data Epoch J2000      Equinox J2000
Constellation	Auriga
Right ascension	05h 38m 38.08510s[1]
Declination	+30° 29′ 32.7054″[1]
Apparent magnitude (V)	5.406[2] (6.29 / 6.21)[3]
Characteristics
Spectral type	G8III + A1IV or B9.5V[4]
U−B color index	+0.25[5]
B−V color index	+0.45[5]
Variable type	suspected[6]
Astrometry
Proper motion (μ)	RA: -21.32[1] mas/yr Dec.: -10.10[1] mas/yr
Distance	163[4] pc
Absolute magnitude (MV)	−0.29[7]
Orbit[4]
Primary	26 Aur A
Companion	26 Aur B
Period (P)	52.735±0.156 yr
Semi-major axis (a)	0.154±0.001" (21.1+3.2 −2.4 AU)
Eccentricity (e)	0.653±0.002
Inclination (i)	124.22±0.29°
Longitude of the node (Ω)	127.08±0.38°
Periastron epoch (T)	1974.927±0.026
Argument of periastron (ω) (secondary)	309.07±0.14°
Details
26 Aur A
Mass	2.1 ± 1.0[4] M☉
26 Aur B
Mass	3.0 ± 0.4[4] M☉
Other designations
26 Aur, BD+30°963, GC 7002, HD 37269, HIP 26536, HR 1914, SAO 58280, PPM 70656, ADS 4229, WDS J05386+3030, GSC 02404-01350
Database references
SIMBAD	data

The distance to this system remains poorly constrained. The new Hipparcos reduction gives a parallax of 5.76±6.42.^[1] The original Hipparcos parallax was given as 7.29±0.96,^[8] leading to a distance of 137.2+20.8
−16.0 pc being assumed in many texts. A distance of 163 pc has been derived from fitting the spectrum.^[4]

26 Aurigae is a visual binary system, and the two stars orbit each other every 52.735 years with an ellipticity of 0.653 and an angular separation 0.154″.^[4] The system is made of a magnitude 6.29^[3] G-type red giant, and a hotter magnitude 6.21^[3] star that has been classified as an early B-type main-sequence star to an A-type subgiant star.^[4] Component A is the cool giant star, the brighter but less massive of the pair.^[9][4] The hotter star is sometimes listed as the primary on the basis of its stronger showing in the blended spectrum.^[10]