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Pi4Orionis

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For other stars with thisBayer designation,seePi Orionis.
π4Orionis
Location of π4Orionis (circled)
Observation data
EpochJ2000.0EquinoxJ2000.0(ICRS)
Constellation Orion
Right ascension 04h51m12.36472s[1]
Declination +05° 36′ 18.3723″[1]
Apparent magnitude(V) 3.685[2]
Characteristics
Spectral type B2 III[3]
U−Bcolor index −0.797[2]
B−Vcolor 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 ± 0.18mas[1]
Distance1,050 ± 60ly
(320 ± 20pc)
Orbit[5]
Period(P)9.5191 d
Eccentricity(e)0.03
Periastronepoch(T)2,418,275.65±10.0
Argument of periastron(ω)
(secondary)		165°
Semi-amplitude(K1)
(primary)		25.8 km/s
Details
π4Ori A
Mass10.95±0.97[6]M☉
Radius9.1[7]R☉
Luminosity19,726[6]L☉
Surface gravity(logg)3.59[8]cgs
Temperature21,874±126[7]K
Metallicity[Fe/H]−0.31[8]dex
Rotational velocity(vsini)38[9]km/s
Age15.4±1.0[10]Myr
Other designations
π4Ori,3 Orionis,BD+05°745,FK5179,HD30836,HIP22549,HR1552,SAO112142[11]
Database references
SIMBADdata

Pi4Orionis(π4Ori, π4Orionis) is abinary starsystem in the western part of theOrionconstellation.It is visible to the naked eye with anapparent visual magnitudeof 3.7.[2]Based upon an annualparallax shiftof 3.1mass,[1]it is located roughly 1,050light-yearsfrom theSun.

This is aspectroscopic binarystar system with anorbital periodof 9.5 days and aneccentricityof 0.03.[5]The primary component is aB-type starwith astellar classificationof B2 III.[3]Thestellar spectrumof π4Ori A shows a strong depletion of the elementboron.[12]It has nearly 11[6]times themass of the Sunand nine times theSun's radius.[7]The star is 15.4[10]million years old and has aprojected rotational velocityof 38 km/s.[9]It shines with 19,726[6]times thesolar luminosityfrom itsouter atmosphereat aneffective temperatureof21,874K.[7]

References

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  1. ^abcdefvan Leeuwen, F. (2007), "Validation of the new Hipparcos reduction",Astronomy and Astrophysics,474(2): 653–664,arXiv:0708.1752,Bibcode:2007A&A...474..653V,doi:10.1051/0004-6361:20078357,S2CID18759600.
  2. ^abcdOja, T. (August 1985), "Photoelectric photometry of stars near the north Galactic pole. II",Astronomy and Astrophysics Supplement Series,61:331–339,Bibcode:1985A&AS...61..331O.
  3. ^abLevato, H. (January 1975), "Rotational velocities and spectral types for a sample of binary systems",Astronomy and Astrophysics Supplement Series,19:91–99,Bibcode:1975A&AS...19...91L.
  4. ^Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities",Carnegie Institute Washington D.C. Publication,Washington: Carnegie Institution of Washington,Bibcode:1953GCRV..C......0W.
  5. ^abPourbaix, D.; et al. (2004), "SB9:The ninth catalogue of spectroscopic binary orbits ",Astronomy & Astrophysics,424(2): 727–732,arXiv:astro-ph/0406573,Bibcode:2004A&A...424..727P,doi:10.1051/0004-6361:20041213,S2CID119387088.
  6. ^abcdHohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants",Astronomische Nachrichten,331(4): 349,arXiv:1003.2335,Bibcode:2010AN....331..349H,doi:10.1002/asna.200911355,S2CID111387483.
  7. ^abcdUnderhill, 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(3): 601–605,Bibcode:1979MNRAS.189..601U,doi:10.1093/mnras/189.3.601.
  8. ^abSoubiran, C.; et al. (June 2010), "The PASTEL catalogue of stellar parameters",Astronomy and Astrophysics,515:A111,arXiv:1004.1069,Bibcode:2010A&A...515A.111S,doi:10.1051/0004-6361/201014247,S2CID118362423.
  9. ^abSimón-Díaz, S.; Herrero, A. (2014), "The IACOB project. I. Rotational velocities in northern Galactic O- and early B-type stars revisited. The impact of other sources of line-broadening",Astronomy & Astrophysics,562:A135,arXiv:1311.3360,Bibcode:2014A&A...562A.135S,doi:10.1051/0004-6361/201322758,S2CID119278062.
  10. ^abTetzlaff, N.; et al. (2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun",Monthly Notices of the Royal Astronomical Society,410(1): 190–200,arXiv:1007.4883,Bibcode:2011MNRAS.410..190T,doi:10.1111/j.1365-2966.2010.17434.x,S2CID118629873.
  11. ^"pi.04 Ori".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved2016-11-18.
  12. ^Kaufer, A. (April 2010), "Observations of light elements in massive stars",Light Elements in the Universe, Proceedings of the International Astronomical Union, IAU Symposium,vol. 268, pp. 317–324,Bibcode:2010IAUS..268..317K,doi:10.1017/S1743921310004291.
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