18 Boötis
Star in the constellation Boötes / From Wikipedia, the free encyclopedia
18 Boötis is a single[9] star in the northern constellation of Boötes,[8] located about 85 light years away from the Sun.[1] It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 5.41.[2] 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]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Boötes |
Right ascension | 14h 19m 16.27966s[1] |
Declination | +13° 00′ 15.4859″[1] |
Apparent magnitude (V) | 5.41[2] |
Characteristics | |
Spectral type | F3 V[3] |
B−V color index | 0.385±0.011[2] |
Astrometry | |
Radial velocity (Rv) | −0.40±0.7[2] km/s |
Proper motion (μ) | RA: +105.273[1] mas/yr Dec.: −31.389[1] mas/yr |
Parallax (π) | 38.1262 ± 0.1323 mas[1] |
Distance | 85.5 ± 0.3 ly (26.23 ± 0.09 pc) |
Absolute magnitude (MV) | 3.33[2] |
Details | |
Mass | 1.31[4] M☉ |
Radius | 1.4[5] R☉ |
Luminosity | 3.90[2] 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 | |
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[2] 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]