18 Boötis

18 Boötis is a single^[9] star in the northern constellation of Boötes,^[8] located about 85 light years away from the Sun.^[2] It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 5.41.^[1] This object is a suspected member of the Ursa Major Moving Group, based on velocity criteria.^[10] It has a magnitude 10.84 optical companion at an angular separation of 163.7″ along a position angle of 219°, as of 2010.^[11]

18 Boötis

Observation data Epoch J2000      Equinox J2000
Constellation	Boötes[1]
Right ascension	14h 19m 16.27966s[2]
Declination	+13° 00′ 15.4859″[2]
Apparent magnitude (V)	5.41[1]
Characteristics
Spectral type	F3 V[3]
B−V color index	0.385±0.011[1]
Astrometry
Radial velocity (Rv)	−0.40±0.7[1] km/s
Proper motion (μ)	RA: +105.273[2] mas/yr Dec.: −31.389[2] mas/yr
Parallax (π)	38.1262±0.1323 mas[2]
Distance	85.5 ± 0.3 ly (26.23 ± 0.09 pc)
Absolute magnitude (MV)	3.33[1]
Details
Mass	1.31[4] M☉
Radius	1.4[5] R☉
Luminosity	3.90[1] L☉
Surface gravity (log g)	4.30[4] cgs
Temperature	6,731±229[4] K
Metallicity [Fe/H]	−0.03±0.04[6] dex
Rotational velocity (v sin i)	40.5±2.0[7] km/s
Age	1.154[4] Gyr
Other designations
18 Boo, BD+13°2782, FK5 1372, GJ 3841, HD 125451, HIP 69989, HR 5365, SAO 100975, WDS J14193+1300[8]
Database references
SIMBAD	data

This is an F-type main-sequence star with a stellar classification of F3 V.^[3] Older surveys gave a class of F5 IV,^[12] showing the luminosity class of a subgiant star. It shows strong evidence for short-term chromospheric variability, although it is not optically variable.^[13]

18 Boötis is an estimated 1.15^[4] billion years old and is spinning with a projected rotational velocity of 40.5 km/s.^[7] It has 1.3^[4] times the mass of the Sun and 1.4^[5] times the Sun's radius. The star is radiating 3.9^[1] times the luminosity of the Sun from its photosphere at an effective temperature of 6,731 K.^[4] An infrared excess has been detected that suggests a cold debris disk is orbiting 34.9 AU from the host star with a blackbody temperature fit of 65 K.^[5]