Psi Centauri
Binary star system in the constellation Centaurus
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Psi Centauri is a binary star[10] system in the southern constellation of Centaurus. Its name is a Bayer designation that is Latinized from ψ Centauri, and abbreviated Psi Cen or ψ Cen. This system is visible to the naked eye as a point of light with a baseline apparent visual magnitude of +4.05.[2] The distance to this system is 250 light years based on parallax.[6] The radial velocity is poorly constrained, but it appears to be slowly drifting away from the Sun at the rate of +2 km/s.[5]
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 14h 20m 33.43s[1] |
| Declination | −37° 53′ 07.1″[1] |
| Apparent magnitude (V) | +4.05[2] |
| Characteristics | |
| Spectral type | A0 IV[3] (B9 and A2)[4] |
| U−B color index | −0.11[3] |
| B−V color index | −0.03[3] |
| Variable type | eclipsing[4] |
| Astrometry | |
| Radial velocity (Rv) | 1.8±0.9[5] km/s |
| Proper motion (μ) | RA: −63.69±0.18[1] mas/yr Dec.: −10.65±0.15[1] mas/yr |
| Parallax (π) | 13.049±0.063 mas[6] |
| Distance | 250.0±1.2 ly (76.64±0.37 pc)[6] |
| Absolute magnitude (MV) | −0.35±0.14[7] |
| Orbit[6] | |
| Period (P) | 38.8121(2) d |
| Semi-major axis (a) | 0.3874±0.0017 AU |
| Eccentricity (e) | 0.550±0.001 |
| Inclination (i) | 89.20±0.13° |
| Longitude of the node (Ω) | 115.79±0.10° |
| Argument of periastron (ω) (secondary) | 19.45±0.27° |
| Semi-amplitude (K1) (primary) | 49.51±0.16 km/s |
| Semi-amplitude (K2) (secondary) | 80.48±0.33 km/s |
| Details[6] | |
| ψ Cen A | |
| Mass | 3.187±0.031 M☉ |
| Radius | 3.814±0.007 R☉ |
| Luminosity | 140+17 −15 L☉ |
| Surface gravity (log g) | 3.811±0.003[8] cgs |
| Temperature | 10,450±300 K |
| Metallicity [Fe/H] | +0.05±0.10 dex |
| Rotation | 1.49±0.26 d[4] |
| Rotational velocity (v sin i) | 123.7[8] km/s |
| Age | 280±10 Myr |
| ψ Cen B | |
| Mass | 1.961±0.015 M☉ |
| Radius | 1.896±0.004 R☉ |
| Luminosity | 17.5+2.6 −2.2 L☉ |
| Surface gravity (log g) | 4.206±0.007[8] cgs |
| Temperature | 8,800±300 K |
| Metallicity [Fe/H] | +0.05±0.10 dex |
| Rotational velocity (v sin i) | 126.9[8] km/s |
| Age | 280±10 Myr |
| Other designations | |
| ψ Cen, CD−37°9336, FK5 1373, GC 19337, HD 125473, HIP 70090, HR 5367, SAO 205453, CCDM J14206-3753, WDS J14206-3753[9] | |
| Database references | |
| SIMBAD | data |
This is a detached eclipsing binary system with the secondary eclipse being total.[4] The pair are orbiting each other with a period of 38.81 days and an eccentricity of 0.55.[6]The brightness of the system dips by 0.28 and 0.16 magnitude during the two eclipses per orbit.[4] The system displays an infrared excess at a wavelength of 60 μm, indicating the presence of a circumstellar debris disk with a temperature of 120 K, orbiting at a distance of 64 AU.[11]
The pair have a combined stellar classification of A0 IV,[3] matching a white-hued A-type subgiant.[2] The two components appear to be at different evolutionary stages.[4] Both have high rotation rates, with projected rotational velocities over 120 km/s.[8] The primary has 3.814 times the Sun's radius while the secondary is 1.896 times.[6] The primary showed evidence of pulsational behavior with 1.996 and 5.127 cycles per day,[4] which suggests it is a slowly pulsating B star.[8] But this remains unconfirmed as of 2017,[12] and the finding may instead be the result of instrumental error.[8]