6 Boötis

This article is about e Boötis and is not to be confused with ε (epsilon) Boötis.

6 Boötis is a binary star^[4] system in the northern constellation of Boötes,^[8] located around 460 light years away from the Sun.^[1] It has the Bayer designation e Boötis; 6 Boötis is the Flamsteed designation.^[8] The system is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.92.^[2] It is moving closer to the Earth with a heliocentric radial velocity of −3 km/s.^[2]

6 Boötis

6 Boötis in optical light.
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Boötes
Right ascension	13h 49m 42.82223s[1]
Declination	+21° 15′ 50.8580″[1]
Apparent magnitude (V)	4.92[2]
Characteristics
Spectral type	K4 III[3] + M8 V[4]
B−V color index	1.432±0.013[2]
Astrometry
Radial velocity (Rv)	−3.71±0.48[1] km/s
Proper motion (μ)	RA: +33.773[1] mas/yr Dec.: +10.842[1] mas/yr
Parallax (π)	7.1527±0.3659 mas[1]
Distance	460 ± 20 ly (140 ± 7 pc)
Absolute magnitude (MV)	−0.49[2]
Orbit[4]
Period (P)	944±8 d
Eccentricity (e)	0.41±0.09
Periastron epoch (T)	2,444,739.5±31.0 JD
Argument of periastron (ω) (secondary)	359±15°
Semi-amplitude (K1) (primary)	1.19±0.15 km/s
Details
Radius	38[5] R☉
Luminosity	430.124[1] L☉
Surface gravity (log g)	1.910[6] cgs
Temperature	4,050[6] K
Metallicity [Fe/H]	−0.24[6] dex
Rotational velocity (v sin i)	2.0[7] km/s
Other designations
e Boötis, 53 Cam, BD+21°2578, FK5 3098, GC 18683, HD 120539, HIP 67480, HR 5201, SAO 83015[8]
Database references
SIMBAD	data

This is a single-lined spectroscopic binary system with an orbital period of 2.58 years and an eccentricity of 0.4.^[4] The visible component is an evolved giant star with a stellar classification of K4 III.^[3] Its measured angular diameter is 2.53±0.12 mas.^[9] At the estimated distance of the star, this yields a physical size of about 38 times the radius of the Sun.^[5] The star is radiating 430^[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,050 K.^[6] Its companion is probably a low mass red dwarf of around class M8 V.^[4]