Delta Boötis
Double star in the northern constellation Boötes / From Wikipedia, the free encyclopedia
Delta Boötis, Latinized from δ Boötis, is a double star in the northern constellation of Boötes, forming the easternmost member of the constellation's kite-shaped asterism of brighter stars.[14] Based upon parallax measurements, it is located at a distance of approximately 120.5 light-years (36.9 parsecs) from the Earth.[1] This star is sometimes called Princeps /ˈprɪnsɛps/,[15] meaning prince or prime in Latin. The origin of this name is unclear, although it usually appears in an astrological context.[16][17] The apparent visual magnitude of this star is 3.5,[2] making it visible to the naked eye even during a Full Moon. The magnitude 7.81[4] companion can be viewed in binoculars or a small telescope.[14]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Boötes |
BD+33 2561 | |
Right ascension | 15h 15m 30.16282s[1] |
Declination | +33° 18′ 53.3925″[1] |
Apparent magnitude (V) | 3.482[2] |
BD+33 2562 | |
Right ascension | 15h 15m 38.34898s[3] |
Declination | +33° 19′ 15.3187″[3] |
Apparent magnitude (V) | 7.81[4] |
Characteristics | |
BD+33 2561 | |
Spectral type | G8 III[5] |
U−B color index | +0.656[2]/ |
B−V color index | +0.951[2]/ |
BD+33 2562 | |
Spectral type | G0 V[4] |
U−B color index | +0.02[4] |
B−V color index | +0.59[4] |
Astrometry | |
BD+33 2561 | |
Radial velocity (Rv) | −12.29±0.16[6] km/s |
Proper motion (μ) | RA: +84.383 mas/yr[1] Dec.: −111.591 mas/yr[1] |
Parallax (π) | 27.0746 ± 0.1256 mas[1] |
Distance | 120.5 ± 0.6 ly (36.9 ± 0.2 pc) |
Absolute magnitude (MV) | +0.700[7] |
BD+33 2562 | |
Radial velocity (Rv) | −11.83±0.18[3] km/s |
Proper motion (μ) | RA: +82.776[3] mas/yr Dec.: –110.040[3] mas/yr |
Parallax (π) | 27.0648 ± 0.0307 mas[3] |
Distance | 120.5 ± 0.1 ly (36.95 ± 0.04 pc) |
Details | |
BD+33 2561 | |
Mass | 1.5[8] M☉ |
Radius | 11.43±0.07[9] R☉ |
Luminosity | 58.1[10] L☉ |
Surface gravity (log g) | 2.38±0.09[10] cgs |
Temperature | 4,810±30[10] K |
Metallicity [Fe/H] | −0.35±0.03[10] dex |
Rotational velocity (v sin i) | 3.6[11] km/s |
BD+33 2562 | |
Mass | 0.98[8] M☉ |
Radius | 0.91±0.02[3] R☉ |
Luminosity | 0.87[8] L☉ |
Temperature | 5,812±67[8] K |
Age | 3.09[8] Gyr |
Other designations | |
A: δ Boo, 49 Boötis, BD+33 2561, FK5 563, HD 135722, HIP 74666, HR 5681, SAO 64589[12] | |
B: BD+33 2562, HIP 74674, SAO 64591[13] | |
Database references | |
SIMBAD | data |
SIMBAD | data |
In Chinese, 七公 (Qī Gōng), meaning Seven Excellencies, refers to an asterism consisting of δ Boötis, 42 Herculis, τ Herculis, φ Herculis, χ Herculis, ν1 Boötis and μ1 Boötis.[18] Consequently, the Chinese name for δ Boötis itself is 七公七 (Qī Gōng qī, English: the Seventh Star of Seven Excellencies.)[19]