[{"@context":"http:\/\/schema.org\/","@type":"BlogPosting","@id":"https:\/\/wiki.edu.vn\/en\/wiki43\/theta2-orionis-wikipedia\/#BlogPosting","mainEntityOfPage":"https:\/\/wiki.edu.vn\/en\/wiki43\/theta2-orionis-wikipedia\/","headline":"Theta2 Orionis – Wikipedia","name":"Theta2 Orionis – Wikipedia","description":"before-content-x4 From Wikipedia, the free encyclopedia after-content-x4 Star in the constellation Orion \u03b82 Orionis The three components of \u03b82 Orionis,","datePublished":"2014-01-07","dateModified":"2014-01-07","author":{"@type":"Person","@id":"https:\/\/wiki.edu.vn\/en\/wiki43\/author\/lordneo\/#Person","name":"lordneo","url":"https:\/\/wiki.edu.vn\/en\/wiki43\/author\/lordneo\/","image":{"@type":"ImageObject","@id":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","height":96,"width":96}},"publisher":{"@type":"Organization","name":"Enzyklop\u00e4die","logo":{"@type":"ImageObject","@id":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","url":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","width":600,"height":60}},"image":{"@type":"ImageObject","@id":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/a\/a5\/Theta2Orionis.jpg\/300px-Theta2Orionis.jpg","url":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/a\/a5\/Theta2Orionis.jpg\/300px-Theta2Orionis.jpg","height":"206","width":"300"},"url":"https:\/\/wiki.edu.vn\/en\/wiki43\/theta2-orionis-wikipedia\/","wordCount":7165,"articleBody":"     (adsbygoogle = window.adsbygoogle || []).push({});before-content-x4From Wikipedia, the free encyclopedia       (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4Star in the constellation Orion\u03b82 OrionisThe three components of \u03b82 Orionis, plus nearby starsCredit: Ian Nartowicz (derived from ESA\/Hubble image)Observation dataEpoch J2000\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Equinox J2000ConstellationOrionARight ascension05h 35m 22.90124s[1]Declination\u221205\u00b0\u00a024\u2032\u00a057.8326\u2033[1]Apparent\u00a0magnitude\u00a0(V)5.02[2]BRight ascension05h 35m 26.40075s[3]Declination\u221205\u00b0\u00a025\u2032\u00a000.7938\u2033[3]Apparent\u00a0magnitude\u00a0(V)6.380[4]CRight ascension05h 35m 31.43111s[5]Declination\u221205\u00b0\u00a025\u2032\u00a016.3717\u2033[5]Apparent\u00a0magnitude\u00a0(V)8.18[6]CharacteristicsSpectral\u00a0typeO9.5IVp[7] + B0.7V[8] + B5V[9]AstrometryARadial velocity (Rv)35.6[10]\u00a0km\/sProper motion (\u03bc) RA:\u00a0+2.630[1]\u00a0mas\/yr Dec.:\u00a0+2.394[1]\u00a0mas\/yr Parallax (\u03c0)2.9728\u00a0\u00b1\u00a00.2136\u00a0mas[1]Distance1,100 \u00b1 80\u00a0ly (340 \u00b1 20\u00a0pc)Absolute\u00a0magnitude\u00a0(MV)\u22124.3[11]BProper motion (\u03bc) RA:\u00a0+1.161[3]\u00a0mas\/yr Dec.:\u00a0+0.162[3]\u00a0mas\/yr Parallax (\u03c0)2.3870\u00a0\u00b1\u00a00.0499\u00a0mas[3]Distance1,370 \u00b1 30\u00a0ly (419 \u00b1 9\u00a0pc)Absolute\u00a0magnitude\u00a0(MV)\u22122.60[4]CProper motion (\u03bc) RA:\u00a0+2.510[5]\u00a0mas\/yr Dec.:\u00a0+3.731[5]\u00a0mas\/yr Parallax (\u03c0)2.4513\u00a0\u00b1\u00a00.0380\u00a0mas[5]Distance1,330 \u00b1 20\u00a0ly (408 \u00b1 6\u00a0pc)Absolute\u00a0magnitude\u00a0(MV)\u22120.6[12]DetailsAMass39[13]\u00a0M\u2609Luminosity107,000[14]\u00a0L\u2609Temperature34,900[14]\u00a0KRotational velocity (v\u00a0sin\u00a0i)133[8]\u00a0km\/sBMass14.8[4]\u00a0M\u2609Radius4.3[4]\u00a0R\u2609Luminosity12,300[4]\u00a0L\u2609Surface gravity (log\u00a0g)4.30[4]\u00a0cgsTemperature29,300[4]\u00a0KRotational velocity (v\u00a0sin\u00a0i)33[8]\u00a0km\/sAge     (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4Bizarrely, \u03b82 Orionis C has a second entry in the Washington Double Star Catalog under the name S490.  The companion is 10th magnitude and actually lies between \u03b82 Ori B and V1073 Ori.[16]\u03b81 Orionis, the well known Trapezium cluster, is only 2 arc minutes away from \u03b82 Orionis A.  Despite the names, \u03b82 Orionis A is marginally brighter than the brightest star in the Trapezium.  The Catalog of Components of Double and Multiple Stars includes the stars of \u03b81 and \u03b82 Ori within the same system of 13 components.There are dozens of much fainter stars in the same field, many of them pre-main-sequence stars still forming from the Orion molecular cloud complex.Properties[edit]The primary component A appears as a 5th magnitude O class subgiant over 100,000 times as luminous as the sun.  The spectral type suggests it is evolving away from the main sequence, although it is thought to be less than 2 million years old.  The spectral peculiarities may be related to close companions or could be caused by the extreme youth of the star.The 6th magnitude component B is an early B main sequence star nearly 30,000 K and over 10,000 times the luminosity of the sun.Component C is another B class main sequence star, but cooler and less than a thousand times the luminosity of the sun.\u03b82 Orionis A system[edit]\u03b82 Orionis A is itself a triple star system.  Its spectral lines were seen to change position periodically, indicating orbital motion.  The first orbit was derived in 1924, indicating a period of 21 days. and a rather eccentric orbit.[17]Speckle interferometry has resolved a companion about 0.3″ away, around 147 AU.  High resolution spectroscopy shows that there is an even closer companion, only about 0.47 AU from the primary, for a total of three stars.  Both companions are thought to be early A or late B with masses of 7-9\u00a0M\u2609.  This helps to explain the high mass and visual luminosity for an O9.5 star at this distance.  The three stars together have nearly the same mass as the O5.5 \u03b81 Orionis C and visually are even brighter.[18]\u03b82 Orionis A also shows unexplained rapidly variable x-ray emission.  The x-rays cannot be explained standard mechanisms such as colliding winds or coronal emissions from an unseen companion.[13]References[edit]^ a b c d e Vallenari, A.;  et\u00a0al. (Gaia Collaboration) (2022). “Gaia Data Release 3. Summary of the content and survey properties”. Astronomy & Astrophysics. arXiv:2208.00211. doi:10.1051\/0004-6361\/202243940. Gaia DR3 record for this source at VizieR.^ Aldoretta, E. J.; Caballero-Nieves, S. M.; Gies, D. R.; Nelan, E. P.; Wallace, D. J.; Hartkopf, W. I.; Henry, T. J.; Jao, W.-C.; Ma\u00edz Apell\u00e1niz, J.; Mason, B. D.; Moffat, A. F. J.; Norris, R. P.; Richardson, N. D.; Williams, S. J. (2015). “The Multiplicity of Massive Stars: A High Angular Resolution Survey with the Guidance Sensor”. The Astronomical Journal. 149 (1): 26. arXiv:1410.0021. Bibcode:2015AJ….149…26A. doi:10.1088\/0004-6256\/149\/1\/26. S2CID\u00a058911264.^ a b c d e Vallenari, A.;  et\u00a0al. (Gaia Collaboration) (2022). “Gaia Data Release 3. Summary of the content and survey properties”. Astronomy & Astrophysics. arXiv:2208.00211. doi:10.1051\/0004-6361\/202243940. Gaia DR3 record for this source at VizieR.^ a b c d e f g h Nieva, Mar\u00eda-Fernanda; Przybilla, Norbert (2014). “Fundamental properties of nearby single early B-type stars”. Astronomy & Astrophysics. 566: A7. arXiv:1412.1418. Bibcode:2014A&A…566A…7N. doi:10.1051\/0004-6361\/201423373. S2CID\u00a0119227033.^ a b c d e Vallenari, A.;  et\u00a0al. (Gaia Collaboration) (2022). “Gaia Data Release 3. Summary of the content and survey properties”. Astronomy & Astrophysics. arXiv:2208.00211. doi:10.1051\/0004-6361\/202243940. Gaia DR3 record for this source at VizieR.^ Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (2001). “Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) – Third edition – Comments and statistics”. Astronomy and Astrophysics. 367 (2): 521. arXiv:astro-ph\/0012289. Bibcode:2001A&A…367..521P. doi:10.1051\/0004-6361:20000451. S2CID\u00a0425754.^ Sota, A.; Ma\u00edz Apell\u00e1niz, J.; Walborn, N. R.; Alfaro, E. J.; Barb\u00e1, R. H.; Morrell, N. I.; Gamen, R. C.; Arias, J. I. (2011). “The Galactic O-Star Spectroscopic Survey. I. Classification System and Bright Northern Stars in the Blue-violet at R ~ 2500”. The Astrophysical Journal Supplement. 193 (2): 24. arXiv:1101.4002. Bibcode:2011ApJS..193…24S. doi:10.1088\/0067-0049\/193\/2\/24. S2CID\u00a0119248206.^ a b c Sim\u00f3n-D\u00edaz, 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\u00a0119278062.^ Houk, N.; Swift, C. (1999). “Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5”. Michigan Spectral Survey. 05: 0. Bibcode:1999MSS…C05….0H.^ Wilson, Ralph Elmer (1953). “General catalogue of stellar radial velocities”. Washington. Bibcode:1953GCRV..C……0W.^ Abbott, D. C. (1978). “The terminal velocities of stellar winds from early-type stars”. Astrophysical Journal. 225: 893. Bibcode:1978ApJ…225..893A. doi:10.1086\/156554.^ Abt, H. A. (1979). “The occurrence of abnormal stars in open clusters”. Astrophysical Journal. 230: 485. Bibcode:1979ApJ…230..485A. doi:10.1086\/157104.^ a b Mitschang, Arik W.; Schulz, Norbert S.; Huenemoerder, David P.; Nichols, Joy S.; Testa, Paola (2011). “Detailed X-Ray Line Properties of \u03b82 Ori a in Quiescence”. The Astrophysical Journal. 734 (1): 14. arXiv:1009.1896. Bibcode:2011ApJ…734…14M. doi:10.1088\/0004-637X\/734\/1\/14. S2CID\u00a015568141.^ a b c d e Hillenbrand, Lynne A. (1997). “On the Stellar Population and Star-Forming History of the Orion Nebula Cluster”. Astronomical Journal. 113: 1733. Bibcode:1997AJ….113.1733H. doi:10.1086\/118389.^ a b Manoj, P.; Maheswar, G.; Bhatt, H. C. (2002). “Non-emission-line young stars of intermediate mass”. Monthly Notices of the Royal Astronomical Society. 334 (2): 419. arXiv:astro-ph\/0204491. Bibcode:2002MNRAS.334..419M. doi:10.1046\/j.1365-8711.2002.05540.x. S2CID\u00a014024844.^ a b Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). “The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog”. The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ….122.3466M. doi:10.1086\/323920.^ Struve, O. (1924). “The orbit of the spectroscopic binary 43 theta-2 Orionis”. Astrophysical Journal. 60: 159. Bibcode:1924ApJ….60..159S. doi:10.1086\/142845.^ Schulz, Norbert S.; Testa, Paola; Huenemoerder, David P.; Ishibashi, Kazunori; Canizares, Claude R. (2006). “X-Ray Variability in the Young Massive Triple \u03b82 Orionis A”. The Astrophysical Journal. 653 (1): 636\u2013646. arXiv:astro-ph\/0608420. Bibcode:2006ApJ…653..636S. doi:10.1086\/508625. S2CID\u00a0119414078.     (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4"},{"@context":"http:\/\/schema.org\/","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"https:\/\/wiki.edu.vn\/en\/wiki43\/#breadcrumbitem","name":"Enzyklop\u00e4die"}},{"@type":"ListItem","position":2,"item":{"@id":"https:\/\/wiki.edu.vn\/en\/wiki43\/theta2-orionis-wikipedia\/#breadcrumbitem","name":"Theta2 Orionis – Wikipedia"}}]}]