Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Boötes |
Right ascension | 15h 37m 49.59790s [1] |
Declination | +40° 21′ 12.3635″ [1] |
Apparent magnitude (V) | +5.24 [2] |
Characteristics | |
Spectral type | G7 III-IV Fe-2 [3] |
U−B color index | +0.53 [2] |
B−V color index | +0.88 [2] |
Astrometry | |
Radial velocity (Rv) | −10.62±0.30 [4] km/s |
Proper motion (μ) |
RA: +61.23
[1]
mas/
yr Dec.: +60.09 [1] mas/ yr |
Parallax (π) | 19.22 ± 0.24 mas [1] |
Distance | 170 ± 2
ly (52.0 ± 0.6 pc) |
Absolute magnitude (MV) | +1.67 [5] |
Details | |
Mass | 1.43 [5] M☉ |
Radius | 5 [4] R☉ |
Luminosity | 17 [4] L☉ |
Surface gravity (log g) | 2.82±0.14 [6] cgs |
Temperature | 4,945±57 [6] K |
Metallicity [Fe/H] | −0.51±0.06 [6] dex |
Rotational velocity (v sin i) | 0.0 [4] km/s |
Age | 3.16 [5] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Phi Boötis (φ Boötis) is a single, [8] yellow-hued star in the northern constellation of Boötes. It is dimly visible to the naked eye with an apparent visual magnitude of +5.24. [2] Based upon an annual parallax shift of 19.22 mas as seen from the Earth, [1] it is located 170 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.09 due to interstellar dust. [5] It is moving closer to the Sun with a radial velocity of −10.6 km/s. [4]
The stellar classification of Phi Boötis is G7 III-IV Fe-2, [3] which would suggest it is an evolving G-type star that shows spectral traits of both a subgiant and a giant star. However, Alves (2000) has it listed as a member of the so-called " red clump", indicating that it is an aging giant star that is generating energy through helium fusion at its core. [9] The 'Fe-2' suffix notation in its class means that it displays a significant underabundance of iron in its spectrum. Around three billion years old, [5] Phi Boötis has an estimated 1.43 [5] times the mass of the Sun and 5 [4] times the Sun's radius. It is radiating 17 [4] times the Sun's luminosity from its photosphere at an effective temperature of about 4,945 K. [6]
Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Boötes |
Right ascension | 15h 37m 49.59790s [1] |
Declination | +40° 21′ 12.3635″ [1] |
Apparent magnitude (V) | +5.24 [2] |
Characteristics | |
Spectral type | G7 III-IV Fe-2 [3] |
U−B color index | +0.53 [2] |
B−V color index | +0.88 [2] |
Astrometry | |
Radial velocity (Rv) | −10.62±0.30 [4] km/s |
Proper motion (μ) |
RA: +61.23
[1]
mas/
yr Dec.: +60.09 [1] mas/ yr |
Parallax (π) | 19.22 ± 0.24 mas [1] |
Distance | 170 ± 2
ly (52.0 ± 0.6 pc) |
Absolute magnitude (MV) | +1.67 [5] |
Details | |
Mass | 1.43 [5] M☉ |
Radius | 5 [4] R☉ |
Luminosity | 17 [4] L☉ |
Surface gravity (log g) | 2.82±0.14 [6] cgs |
Temperature | 4,945±57 [6] K |
Metallicity [Fe/H] | −0.51±0.06 [6] dex |
Rotational velocity (v sin i) | 0.0 [4] km/s |
Age | 3.16 [5] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Phi Boötis (φ Boötis) is a single, [8] yellow-hued star in the northern constellation of Boötes. It is dimly visible to the naked eye with an apparent visual magnitude of +5.24. [2] Based upon an annual parallax shift of 19.22 mas as seen from the Earth, [1] it is located 170 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.09 due to interstellar dust. [5] It is moving closer to the Sun with a radial velocity of −10.6 km/s. [4]
The stellar classification of Phi Boötis is G7 III-IV Fe-2, [3] which would suggest it is an evolving G-type star that shows spectral traits of both a subgiant and a giant star. However, Alves (2000) has it listed as a member of the so-called " red clump", indicating that it is an aging giant star that is generating energy through helium fusion at its core. [9] The 'Fe-2' suffix notation in its class means that it displays a significant underabundance of iron in its spectrum. Around three billion years old, [5] Phi Boötis has an estimated 1.43 [5] times the mass of the Sun and 5 [4] times the Sun's radius. It is radiating 17 [4] times the Sun's luminosity from its photosphere at an effective temperature of about 4,945 K. [6]