VY Velikega psa
VY Velikega psa (VY Canis Majoris ali VY CMa) je rdeča velikanka, ki se nahaja v ozvezdju Velikega psa. S polmerom med 1.800 in 2.100 Sončevih polmerov (tj. premer približno 2,7 milijard km) je največja znana zvezda v vesolju. Za ponazoritev, potrebno bi bilo 7 · 1015 Zemelj, da bi napolnili zvezdo. Poleg tega je tudi najsvetlejša znana zvezda v vesolju, njen izsev pa znaša 4,3 · 105 L☉.[14]
VY CMa je zvezda razreda M z efektivno temperaturo približno 3.000 K, kar jo uvršča v zgornji desni kot v Hertzsprung–Russllovem diagramu. V svojem glavnem nizu je bila verjetno zvezda razreda O[15] z maso od 30-40 m☉.[16] Za razliko od večine drugih hiperorjakinj, ki se nahajajo v dvozvezdjih ali pa v sistemih z več zvezdami, se VY CMa nahaja sama zase. Je polpravilna spremenljivka in ima periodo 2.000 dni.[17]
Prva dokumentirana omemba zvezde se je pojavila v zvezdnem katalogu Jérômeja Lalanda, 7. marca 1801.[18]
Glej tudi
uredi- R136a1, najmasivnejša zvezda
Sklici
uredi- ↑ 1,0 1,1 1,2 1,3 1,4 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.
- ↑ 2,0 2,1 »GCVS Query=VY CMa«. General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. Pridobljeno 24. novembra 2010.
- ↑ 3,0 3,1 3,2 3,3 3,4 3,5 3,6 Wittkowski, M.; Hauschildt, P.H.; Arroyo-Torres, B.; Marcaide, J.M. (5. april 2012). »Fundamental properties and atmospheric structure of the red supergiant VY CMa based on VLTI/AMBER spectro-interferometry«. Astronomy & Astrophysics. 540: L12. arXiv:1203.5194. Bibcode:2012A&A...540L..12W. doi:10.1051/0004-6361/201219126.
- ↑ Massey, Philip; Levesque, Emily M.; Plez, Bertrand (1. avgust 2006). »Bringing VY Canis Majoris down to size: an improved determination of its effective temperature«. The Astrophysical Journal. 646 (2): 1203–1208. arXiv:astro-ph/0604253. Bibcode:2006ApJ...646.1203M. doi:10.1086/505025.
- ↑ Lipscy, S. J.; Jura, M.; Reid, M. J. (10. junij 2005). »Radio photosphere and mass-loss envelope of VY Canis Majoris«. The Astrophysical Journal. 626 (1): 439–445. arXiv:astro-ph/0502586. Bibcode:2005ApJ...626..439L. doi:10.1086/429900.
- ↑ 6,0 6,1 6,2 6,3 6,4 Ducati, J. R (2002). »VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system«. VizieR On-line Data Catalog. Bibcode:2002yCat.2237....0D.
- ↑ De Beck, E.; Decin, L.; De Koter, A.; Justtanont, K.; Verhoelst, T.; Kemper, F.; Menten, K. M. (2010). »Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles. II. CO line survey of evolved stars: Derivation of mass-loss rate formulae«. Astronomy and Astrophysics. 523: A18. arXiv:1008.1083. Bibcode:2010A&A...523A..18D. doi:10.1051/0004-6361/200913771.
- ↑ 8,0 8,1 Serkowski, K (1969). »Large Optical Polarization of the OH Emission Source VY Canis Majoris«. The Astrophysical Journal. 156: L139. Bibcode:1969ApJ...156L.139S. doi:10.1086/180366.
- ↑ »VSX: Detail for VY CMa«. American Association of Variable Star Observers. Pridobljeno 20. julija 2018.
- ↑ Humphreys, Roberta M.; Helton, L. Andrew; Jones, Terry J. (2007). »The Three-Dimensional Morphology of VY Canis Majoris. I. The Kinematics of the Ejecta«. The Astronomical Journal. 133 (6): 2716–2729. arXiv:astro-ph/0702717. Bibcode:2007AJ....133.2716H. doi:10.1086/517609.
- ↑ 11,0 11,1 11,2 Zhang, B.; Reid, M. J.; Menten, K. M.; Zheng, X. W. (Januar 2012). »Distance and Kinematics of the Red Hypergiant VY CMa: VLBA and VLA Astrometry«. The Astrophysical Journal. 744 (1): 23. arXiv:1109.3036. Bibcode:2012ApJ...744...23Z. doi:10.1088/0004-637X/744/1/23.
- ↑ David Darling. »VY Canis Majoris«. Pridobljeno 9. julija 2018.
- ↑ Matsuura, Mikako; Sargent, B; Swinyard, Bruce; Yates, Jeremy; Royer, P; Barlow, M. J; Boyer, Martha; Decin, L; Khouri, Theo; Meixner, Margaret; van Loon, Jacco Th; Woods, Paul M (2016). »The mass-loss rates of red supergiants at low metallicity: Detection of rotational CO emission from two red supergiants in the Large Magellanic Cloud«. Monthly Notices of the Royal Astronomical Society. 462 (3): 2995–3005. arXiv:1608.01729. Bibcode:2016MNRAS.462.2995M. doi:10.1093/mnras/stw1853.
- ↑ Humphreys, Roberta M. (2006). »VY Canis Majoris: The Astrophysical Basis of Its Luminosity«: astro–ph/0610433. arXiv:astro-ph/0610433. Bibcode:2006astro.ph.10433H.
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(pomoč) - ↑ Lada, Charles J.; Reid, Mark J. (1. januar 1978). »CO observations of a molecular cloud complex associated with the bright rim near VY Canis Majoris«. The Astrophysical Journal. 219: 95–104. Bibcode:1978ApJ...219...95L. doi:10.1086/155758.
- ↑ Wittkowski, M.; Langer, N.; Weigelt, G. (2004). »Diffraction-limited speckle-masking interferometry of the red supergiant VY CMa«. Astronomy and Astrophysics. 340 (2004): 77–87. arXiv:astro-ph/9811280. Bibcode:1998A&A...340L..39W.
- ↑ Monnier, J.D.; Geballe, T.R.; Danchi, W.C. (1998). »Temporal variations of midinfrared spectra in late-type stars«. The Astrophysical Journal. American Astronomical Society. 502: 833–846. doi:10.1086/305945.
- ↑ Robinson, L.J. (1971). »Three somewhat overlooked facets of VY Canis Majoris«. Commission 27 of the I. A. U., Information Bulletin on Variable Stars. Konkoly Observatory, Budapest (599).