Phi Centauri

φ Centauri
Location of φ Centauri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 13h 58m 16.27s[1]
Declination −42° 06′ 02.7″[1]
Apparent magnitude (V) +3.745[2]
Characteristics
Spectral type B2 IV[3]
U−B color index −0.851[4]
B−V color index −0.222[4]
Astrometry
Radial velocity (Rv)+5.3±1.5[5] km/s
Proper motion (μ) RA: −22.77±0.15[1] mas/yr
Dec.: −20.13±0.12[1] mas/yr
Parallax (π)6.21 ± 0.17 mas[1]
Distance530 ± 10 ly
(161 ± 4 pc)
Absolute magnitude (MV)−2.20[2]
Details
Mass8.5±0.3[3] M☉
Radius4.19±0.35[6] R☉
Luminosity4,000[7] L☉
Surface gravity (log g)4.08±0.07[6] cgs
Temperature21,638±388[6] K
Rotational velocity (v sin i)79[8] km/s
Age18.0±3.2[3] Myr
Other designations
φ Cen, CD−41° 8329, GC 18874, HD 121743, HIP 68245, HR 5248, SAO 224577
Database references
SIMBADdata

Phi Centauri, Latinized from φ Centauri, is a blue-white hued star in the southern constellation Centaurus. It is visible to the naked eye with an apparent visual magnitude of +3.7.[2] The annual parallax shift is 6.21 mas[1] as measured from Earth, which yields a distance estimate of around 530 light years. It is moving further from the Sun with a radial velocity of +5 km/s.[5]

This is a B-type subgiant star with a stellar classification of B2 IV.[3] It has no known companions, but does show radial velocity variations and higher order pulsations in the spectrum.[9] The star is just 18[3] million years old with 8.5[3] times the mass of the Sun and has 4.2[6] times the Sun's radius. It is radiating around 4,000[7] times the Sun's luminosity from its photosphere at an effective temperature of about 21,638 K.[6]

This star is a proper motion member of the Upper Centaurus–Lupus sub-group in the Scorpius–Centaurus OB association, the nearest such co-moving association of massive stars to the Sun.[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 Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference mnras410_1_190 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Moreno1968 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 c d e Cite error: The named reference aj129_3_1642 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference aaa216_1_44 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Wolff2007 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Alecian2014 was invoked but never defined (see the help page).