Psi Centauri

Psi Centauri
Location of ψ Centauri (circled)
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)12.60 ± 0.20 mas[1]
Distance259 ± 4 ly
(79 ± 1 pc)
Absolute magnitude (MV)−0.35±0.14[6]
Orbit[4]
Period (P)38.81252±0.00029 d
Eccentricity (e)0.55408±0.00024
Inclination (i)88.955±0.012°
Argument of periastron (ω)
(secondary)		20.095±0.098°
Semi-amplitude (K1)
(primary)		49.01±0.11[7] km/s
Semi-amplitude (K2)
(secondary)		79.92±0.15[7] km/s
Details
ψ Cen A
Mass3.114[8] M☉
Radius3.634[8] R☉
Luminosity141[8] L☉
Surface gravity (log g)3.811±0.003[7] cgs
Temperature10,450[8] K
Rotation1.49±0.26 d[4]
Rotational velocity (v sin i)123.7[7] km/s
Age269[6] Myr
ψ Cen B
Mass1.909[8] M☉
Radius1.811[8] R☉
Luminosity18[8] L☉
Surface gravity (log g)4.206±0.007[7] cgs
Temperature8,800[8] K
Rotational velocity (v sin i)126.9[7] km/s
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
SIMBADdata

Psi Centauri, which is Latinized from ψ Centauri, is a binary star[10] system in the southern constellation of Centaurus. It is visible to the naked eye with a baseline apparent visual magnitude of +4.05.[2] The distance to this system is approximately 259 light years based on parallax.[1] 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]

A light curve for Psi Centauri, plotted from data published by Bruntt et al. (2006)[4]

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.[10] 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.[7] The primary has 3.6 times the Sun's radius while the secondary is 1.8 times.[8] 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.[7] But this remains unconfirmed as of 2017,[12] and the finding may instead be the result of instrumental error.[7]

  1. ^ a b c d e f Cite error: The named reference van Leeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Buscombe1962 was invoked but never defined (see the help page).
  4. ^ a b c d e f g h i Cite error: The named reference Bruntt2006 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Gerbaldi1999 was invoked but never defined (see the help page).
  7. ^ a b c d e f g h i Cite error: The named reference Mantegazza2010 was invoked but never defined (see the help page).
  8. ^ a b c d e f g h i Cite error: The named reference Eker2015 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Rhee2007 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Liakos2017 was invoked but never defined (see the help page).