Pi4 Orionis
Binary star system in the constellation Orion
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]
References
^ a b c d e f van 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 , S2CID 18759600 .
^ a b c d Oja, 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 .
^ a b Levato, 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 .
^ 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 .
^ a b Pourbaix, 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 , S2CID 119387088 .
^ a b c d Hohle, 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 , S2CID 111387483 .
^ a b c d 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 (3): 601–605, Bibcode :1979MNRAS.189..601U , doi :10.1093/mnras/189.3.601 .
^ a b Soubiran, 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 , S2CID 118362423 .
^ a b Simón-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 , S2CID 119278062 .
^ a b Tetzlaff, 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 , S2CID 118629873 .
^ "pi.04 Ori" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2016-11-18 .
^ 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, no. S268, pp. 317–324, Bibcode :2010IAUS..268..317K , doi :10.1017/S1743921310004291 .