12 Boötis

12 Boötis is a spectroscopic binary^[7] in the constellation Boötes. It is approximately 122 light years from Earth.^[1]

12 Boötis

Location of 12 Boötis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Boötes
Right ascension	14h 10m 23.93342s[1]
Declination	25° 05′ 30.0394″[1]
Apparent magnitude (V)	4.83[2]
Characteristics
Spectral type	F9IVw[3]
U−B color index	+0.07[2]
B−V color index	+0.54[2]
Astrometry
Radial velocity (Rv)	+9.646±0.013[4] km/s
Proper motion (μ)	RA: −23.43[1] mas/yr Dec.: −59.79[1] mas/yr
Parallax (π)	27.917 ± 0.044 mas[4]
Distance	116.8 ± 0.2 ly (35.82 ± 0.06 pc)
Absolute magnitude (MV)	2.00[5]
Orbit[4]
Primary	12 Boo Aa
Companion	12 Boo Ab
Period (P)	9.6045601±0.0000036 d
Semi-major axis (a)	3.4706±0.0055 mas
Eccentricity (e)	0.19214±0.00015
Inclination (i)	107.95±0.12°
Longitude of the node (Ω)	80.49±0.10°
Periastron epoch (T)	2,454,100.43572±0.00070
Argument of periastron (ω) (secondary)	286.832±0.029°
Semi-amplitude (K1) (primary)	67.189±0.011 km/s
Semi-amplitude (K2) (secondary)	69.311±0.014 km/s
Details
12 Boo Aa
Mass	1.4109±0.0028[4] M☉
Radius	2.450[6] R☉
Luminosity	7.531 L☉
Surface gravity (log g)	3.73[5] cgs
Temperature	6115[6] K
Metallicity [Fe/H]	−0.065[4] dex
12 Boo Ab
Mass	1.3677±0.0028[4] M☉
Radius	1.901[6] R☉
Luminosity	4.692[6] L☉
Temperature	6200[6] K
Metallicity [Fe/H]	−0.065[6] dex
Other designations
d Boötis, 12 Boötis, FK5 522, GC 19127, HIP 69226, HR 5304, HD 123999, GJ 9470, BD+25°2737, SAO 83203, WDS J14104+2506AB, CCDM 14104+2505
Database references
SIMBAD	data

12 Boötis is a yellow-white F-type subgiant with an apparent magnitude of +4.82. It is a spectroscopic binary pair which orbit around its centre of mass once every 9.6045 days,^[3] with an estimated separation of 0.0035".^[8] The two stars have similar masses around 1.4 M_☉, both are slightly hotter than the Sun and about twice as large.^[4]

A further companion, 12 Boötis B, was reported with a separation of approximately one arcsecond in 1989, but subsequent surveys have repeatedly failed to detect this companion.^[3]