Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Centaurus |
Right ascension | 13h 45m 41.24482s [1] |
Declination | −33° 02′ 37.3997″ [1] |
Apparent magnitude (V) | +4.23 [2] |
Characteristics | |
Spectral type | F2 V [3] |
U−B color index | +0.00 [4] |
B−V color index | +0.38 [4] |
Astrometry | |
Radial velocity (Rv) | −21.5±0.6 [5] km/s |
Proper motion (μ) |
RA: −462.49±0.18
[1]
mas/
yr Dec.: −146.49±0.16 [1] mas/ yr |
Parallax (π) | 51.54 ± 0.19 mas [1] |
Distance | 63.3 ± 0.2
ly (19.40 ± 0.07 pc) |
Absolute magnitude (MV) | +2.81 [6] |
Orbit [7] | |
Period (P) | 9.94480±0.00441 d |
Eccentricity (e) | 0.247±0.105 |
Periastron epoch (T) | 2,422,737.382 ± 3.35 JD |
Argument of periastron (ω) (secondary) | 137.7±25.4° |
Semi-amplitude (K1) (primary) | 6.00±0.75 km/s |
Details | |
Mass | 1.35 [6] M☉ |
Luminosity (bolometric) | 5.857 [8] L☉ |
Surface gravity (log g) | 4.25±0.14 [9] cgs |
Temperature | 6,898±235 [9] K |
Metallicity [Fe/H] | −0.09 [8] dex |
Rotation | 2.42±0.22 [8] |
Rotational velocity (v sin i) | 86 [6] km/s |
Age | 1.193 [9] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
1 Centauri, or i Centauri, [10] is a yellow-white-hued binary star [7] system in the southern constellation Centaurus. It can be seen with the naked eye, having an apparent visual magnitude of +4.23. [2] Based upon an annual parallax shift of 51.54 mas as seen from Earth's orbit, it is located 51.5 light-years from the Sun. The system is moving closer to the Sun with a radial velocity of −21.5 km/s. [5]
Spectrographic images taken at the Cape Observatory between 1921 and 1923 showed this star has a variable radial velocity, which indicated this is a single-lined spectroscopic binary star system. The pair have an orbital period of 9.94 days and an eccentricity of about 0.2. [7]
The primary component has received a number of different stellar classifications. For example, Jaschek et al. (1964) lists F0V, F2III, F4III and F4IV, thus ranging in evolutionary state from an ordinary F-type main-sequence star to a giant star. [11] More recently, Houk (1982) listed a class of F3 V, [12] matching an ordinary main-sequence star that is generating energy through hydrogen fusion at its core. The NStars project gives it a classification of F2 V. [3]