Pi4 Orionis

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π4 Orionis
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The location of Pi4 Orionis (π4) in the constellation of Orion.
Observation data
Epoch J2000      Equinox J2000
Constellation Orion
Right ascension 04h 51m 12.4s
Declination 05° 36′ 18.4″
Apparent magnitude (V) 3.67
Spectral type B2 III
U−B color index −0.81
B−V color index −0.16
Radial velocity (Rv) 23.3 km/s
Proper motion (μ) RA: −3.62 mas/yr
Dec.: 1.03 mas/yr
Parallax (π) 2.59 ± 0.80 mas
Distance approx. 1,300 ly
(approx. 400 pc)
Radius 9.1[1] R
Surface gravity (log g) 3.5[1] cgs
Temperature 21,874 ± 126[1] K
Other designations
π4 Orionis, 3 Orionis, HR 1552, HD 30836, SAO 112142, FK5 179, HIP 22579.
Database references

Pi4 Orionis4 Ori, π4 Orionis) is a spectroscopic binary star in the constellation Orion. It is about 1,300 light years away and is one of the most luminous stars known. It is one of a series of stars that share the Bayer designation Pi Orionis.


  1. ^ a b c Underhill, A. B. et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society 189: 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601