HD 129132 is a triple star[5] system in the northern constellation of Boötes. It is dimly visible to the naked eye with a combined apparent visual magnitude of 6.13.[2] The distance to this system is approximately 382 light years based on parallax, and it is drifting further away from the Sun with a radial velocity of +1.7 km/s.[1]
Observation data Epoch J2000.0 Equinox J2000.0 | |
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Constellation | Boötes |
Right ascension | 19h 40m 05.79185s[1] |
Declination | +18° 00′ 50.0046″[1] |
Apparent magnitude (V) | 6.13[2] |
Characteristics | |
Spectral type | G0V[3] or F4III[4] |
B−V color index | 0.434±0.004[2] |
Astrometry | |
Radial velocity (Rv) | +1.667±0.0024[1] km/s |
Proper motion (μ) | RA: +14.630[1] mas/yr Dec.: −20.160[1] mas/yr |
Parallax (π) | 8.5307 ± 0.1848 mas[1] |
Distance | 382 ± 8 ly (117 ± 3 pc) |
Absolute magnitude (MV) | 0.82 |
Orbit[5] | |
Primary | A |
Companion | B |
Period (P) | 101.606±0.003 d |
Semi-major axis (a) | ≥26.4±0.2 Gm |
Eccentricity (e) | 0.117±0.007 |
Periastron epoch (T) | 2,442,478.0±0.8 HJD |
Semi-amplitude (K1) (primary) | 19.0±0.1 km/s |
Orbit[5] | |
Primary | AB |
Companion | C |
Period (P) | 3,385±7 d |
Semi-major axis (a) | 0.074±0.001" (407±6 Gm) |
Eccentricity (e) | 0.073±0.010 |
Inclination (i) | 104.6±0.5° |
Periastron epoch (T) | 2,442,880±40 HJD |
Argument of periastron (ω) (secondary) | 91.4±4.1° |
Semi-amplitude (K1) (primary) | 8.5±0.1 km/s |
Details | |
A | |
Mass | 1.99[6] M☉ |
Radius | 17.0+1.7 −1.6[1] R☉ |
Luminosity | 236.1+5.9 −5.7[1] L☉ |
Surface gravity (log g) | 3.41[6] cgs |
Temperature | 5,488+275 −258[1] K |
Rotational velocity (v sin i) | 25.3[6] km/s |
Age | 1.00[6] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
This system was found to be a spectroscopic binary by the Dominion Astrophysical Observatory in 1923. It was then shown to be a triple star system in 1937 by William E. Harper and Guy H. Blanchet.[8] The inner pair have an orbital period of 101.6 days and an eccentricity of 0.117, with the primary forming the visible component of this pair. The third component forms a visual system with the inner pair, orbiting with a period of 9.27 years and an eccentricity of 0.073.[5][9]
The primary component appears to be an aging giant star with a stellar classification of F4III,[4] although it has also been classed as a G-type main-sequence star of type G0V.[3] It is around a billion years old with twice the mass of the Sun.[6] The star has expanded to 17[1] times the Sun's radius and is radiating 236[1] times the luminosity of the Sun at an effective temperature of 5,488 K.[1] It is spinning with a projected rotational velocity of 25.3 km/s.[6]
Constellation of Boötes | |||||||||||
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