Pi4 Orionis

For other stars with this Bayer designation, see Pi Orionis.
π4 Orionis
Location of π4 Orionis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Orion
Right ascension 04h 51m 12.36472s[1]
Declination +05° 36′ 18.3723″[1]
Apparent magnitude (V) 3.685[2]
Characteristics
Spectral type B2 III[3]
U−B color index −0.797[2]
B−V color index −0.180[2]
Astrometry
Radial velocity (Rv)23.3[4] km/s
Proper motion (μ) RA: −2.21[1] mas/yr
Dec.: +0.85[1] mas/yr
Parallax (π)3.10 ± 0.18 mas[1]
Distance1,050 ± 60 ly
(320 ± 20 pc)
Orbit[5]
Period (P)9.5191 d
Eccentricity (e)0.03
Periastron epoch (T)2,418,275.65±10.0
Argument of periastron (ω)
(secondary)		165°
Semi-amplitude (K1)
(primary)		25.8 km/s
Details
π4 Ori A
Mass10.95±0.97[6] M☉
Radius9.1[7] R☉
Luminosity19,726[6] L☉
Surface gravity (log g)3.59[8] cgs
Temperature21,874±126[7] K
Metallicity [Fe/H]−0.31[8] dex
Rotational velocity (v sin i)38[9] km/s
Age15.4±1.0[10] Myr
Other designations
π4 Ori, 3 Orionis, BD+05°745, FK5 179, HD 30836, HIP 22549, HR 1552, SAO 112142[11]
Database references
SIMBADdata

Pi4 Orionis (π4 Ori, π4 Orionis) is a binary star system in the western part of the Orion constellation. It is visible to the naked eye with an apparent visual magnitude of 3.7.[2] Based upon an annual parallax shift of 3.1 mass,[1] it is located roughly 1,050 light-years from the Sun.

This is a spectroscopic binary star system with an orbital period of 9.5 days and an eccentricity of 0.03.[5] The primary component is a B-type star with a stellar classification of B2 III.[3] The stellar spectrum of π4 Ori A shows a strong depletion of the element boron.[12] It has nearly 11[6] times the mass of the Sun and nine times the Sun's radius.[7] The star is 15.4[10] million years old and has a projected rotational velocity of 38 km/s.[9] It shines with 19,726[6] times the solar luminosity from its outer atmosphere at an effective temperature of 21,874 K.[7]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Oja1985 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Levato1975 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference gcsrv1953 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Pourbaix2004 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference Hohle2010 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference Underhill1979 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Soubiran2010 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference simon-diaz2014 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Kaufer2010 was invoked but never defined (see the help page).