V901 Orionis

	V901 Orionis
Observationsdata; Epok: J2000.0
Stjärnbild	Orion
Rektascension	23t 57m 58,477s
Deklination	+15° 57′ 10,09″
Skenbar magnitud ()	+6,99 (6,97 - 7,02)
Stjärntyp
Spektraltyp	B2 V
B–V	-0,139 ± 0,007
Variabeltyp	SX Arietis-variabel
Astrometri
Radialhastighet ()	+14,66 ± 0,25 km/s
Egenrörelse (µ)	RA: +2,743 mas/år; Dek.: +1,671 mas/år
Parallax ()	2,5463 ± 0,0524
Avstånd	1 280 ± 30 lå (393 ± 8 pc)
Absolut magnitud ()	-0,77
Detaljer
Massa	8,3 ± 0,3 M☉
Radie	3,2 R☉
Luminositet	1 995 +823−583 L☉
Temperatur	22 000 ± 1 000 K
Vinkelhastighet	101 km/s
Ålder	3,98 miljoner år
Andra beteckningar
	Landstreets stjärna, HD 37776, AG-01 624, ALS 8488, AP J05405637-0130257, BD-01 1005, CEL 923, GSC 04767-01406, HIC 26742, HIP 26742, LS VI -01 3, 2MASS J05405637-0130257, PPM 175998, SAO 132446, TD1 5138, TYC 4767-1406-1, uvby98 100037776, V901 Orionis, VDB 51, Gaia DR2 3217413606922372992, Gaia DR3 3217413606922372992

V901 Orionis är en variabel stjärna i stjärnbilden Orion. Den är ibland känd som Landstreets stjärna och har beteckningen HD 37776 i Henry Draperkatalogen. Med en skenbar magnitud som varierar kring 6,99, är den den mycket svår att se för blotta ögat även under bästa ljusförhållanden. Baserat på parallaxmätningar från jorden är den belägen på ett avstånd av 1 280 ± 30 ljusår (393 ± 8 parsec). Stjärnan rör sig bort från solsystemet med en radialhastighet av 15 km/s.

V901 Orionis är medlem i Orion OB1- föreningen av medgående stjärnor och är inbäddad i emissionsnebulosan IC 432. Den är en kandidatmedlem i Orion B-komplexets stjärnbildningsregion.

Observationer

V901 Orionis befanns år 1976 vara en heliumrik variabel stjärna. Det visade sig att den hade en hög rotationshastighet och uppvisade ett överskott av infraröd strålning. Magnetfältsmätningar visade en multipolfördelning och en period på 1,5 dygn. Detta var den första stjärnan som upptäcktes där en kvadrupolliknande geometri av magnetfältet dominerade över dipolfältet som finns i de flesta stjärnor.

År 2007 upptäcktes att V901 Orionis genomgick en rotationsförändring, troligen på grund av förlust av rörelsemängdsmoment från en magnetiskt avgränsad stjärnvind. Rotationsbromsningen i stjärnan är 0,54 ± 0,02 s per år, en rekordnivå för magnetiska kemiskt säregna stjärnor. Överraskande nog visade en långtidsstudie av rotationsperioden en stadig ökning fram till 2003, varefter perioden började minska. Detta kan vara resultatet av en växelverkan mellan ett tunt, magnetiskt avgränsat yttre hölje och en snabbare roterande inre kropp.

Egenskaper

V901 Orionis är en massiv, heliumstark, magnetisk kemiskt säregen stjärna av spektralklass B2 V. Den klassificeras som en SX Arietis-variabel vars skenbara magnitud varierar från 6,97 till 7,02 med en period av 1,5385 dygn. Ljusvariationen tros bero på ojämn ytfördelning av helium och kisel. Magnetfältets topologi är den mest komplexa som någonsin hittats för en stjärna av tidig typ (det vill säga en huvudseriestjärna med högre massa).

Stjärnmodeller målar upp V901 Orionis som en ung stjärna med en uppskattad ålder på fyra miljoner år, som roterar med en beräknad rotationshastighet på 101 km/s. Den har uppskattningsvis en massa motsvarande 8,3 solmassor och en radie av 3,2 solradier. Stjärnan utstrålar energi motsvarande nästan 2 000 gånger solens luminositet från dess fotosfär vid en effektiv temperatur på ca 22 000 K.

Referenser

Den här artikeln är helt eller delvis baserad på material från engelskspråkiga Wikipedia, V901 Orionis, 5 januari 2026..

Noter

1 2 3 4 5 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875. Gaia DR3 record for this source at VizieR.
1 2 3 4 Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085. V901 Ori data
1 2 Houk, N.; Smith-Moore, M. (1988), Declinations -26°.0 to -12°.0, Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars, vol. 4, Bibcode:1988mcts.book.....H.
1 2 Jönsson, Henrik; et al. (17 augusti 2020), "APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South", The Astronomical Journal, 160 (3), American Astronomical Society: 120, arXiv:2007.05537, Bibcode:2020AJ....160..120J, doi:10.3847/1538-3881/aba592, ISSN 0004-6256.
1 2 3 4 5 6 7 Shultz, M. E.; et al. (juni 2022), "MOBSTER - VI. The crucial influence of rotation on the radio magnetospheres of hot stars", Monthly Notices of the Royal Astronomical Society, 513 (1): 1429–1448, arXiv:2201.05512, Bibcode:2022MNRAS.513.1429S, doi:10.1093/mnras/stac136.
1 2 Yu, Jie; et al. (2023), "Revised Extinctions and Radii for 1.5 Million Stars Observed by APOGEE, GALAH, and RAVE", The Astrophysical Journal Supplement Series, 264 (2): 41, arXiv:2206.00046, Bibcode:2023ApJS..264...41Y, doi:10.3847/1538-4365/acabc8
1 2 Shultz, M. E.; et al. (2019), "The magnetic early B-type stars - III. A main-sequence magnetic, rotational, and magnetospheric biography", Monthly Notices of the Royal Astronomical Society, 490 (1): 274, arXiv:1909.02530, Bibcode:2019MNRAS.490..274S, doi:10.1093/mnras/stz2551.
1 2 3 4 Mikulášek, Z.; et al. (november 2020), "What's New with Landstreet's Star HD 37776 (V901 Ori)?", in Wade, Gregg; et al. (eds.), Stellar Magnetism: A Workshop in Honour of the Career and Contributions of John D. Landstreet, held 8-11 July 2019 in London, Canada, Proceedings of the Polish Astronomical Society, vol. 11, pp. 46–53, arXiv:1912.04121, Bibcode:2020pase.conf...46M, ISBN 978-83-950430-9-3.
↑ https://simbad.cds.unistra.fr/simbad/sim-id?Ident=V901+Ori. Hämtad 2026-03-26.
↑ "V901 Ori", SIMBAD, Centre de données astronomiques de Strasbourg, hämtad 2025-11-03.
1 2 Semenko, Eugene; et al. (september 2022), "Spectropolarimetry of magnetic Chemically Peculiar stars in the Orion OB1 association", Monthly Notices of the Royal Astronomical Society, 515 (1): 998–1011, arXiv:2207.00337, Bibcode:2022MNRAS.515..998S, doi:10.1093/mnras/stac1864.
↑ Román-Zúñiga, Carlos G.; et al. (February 2023), "Stellar Properties for a Comprehensive Collection of Star-forming Regions in the SDSS APOGEE-2 Survey", The Astronomical Journal, 165 (2), id. 51, arXiv:2211.09217, Bibcode:2023AJ....165...51R, doi:10.3847/1538-3881/aca3a4.
↑ Groote, D.; Kaufmann, J. P. (1981), "The helium-rich variable star HD 37776", Chemically peculiar stars of the upper main sequence; International Conference on Astrophysics, 23rd, Liege, Belgium, June 23-26, 1981, Reports. (A82-37717 18-39), vol. 23, Liege: Universite de Liege, pp. 435–438, Bibcode:1981LIACo..23..435G.
↑ Thompson, I. B.; Landstreet, J. D. (February 1985), "The extraordinary magnetic variation of the helium-strong star HD 37776 : a quadrupole field configuration.", Astrophysical Journal, 289: L9–L13, Bibcode:1985ApJ...289L...9T, doi:10.1086/184424.
↑ Krtička, J.; et al. (March 2007), Stefl, S.; et al. (eds.), "The Nature of Light Variations of the Helium Strong Chemically Peculiar Star HD 37776", Active OB-Stars: Laboratories for Stellar and Circumstellar Physics. Proceedings of the conference held 29 August - 2 september, 2005 at Hokkai-Gakuen University, Sapporo, Japan, ASP Conference Series, vol. 361, San Francisco: Astronomical Society of the Pacific, p. 454, arXiv:astro-ph/0509751, Bibcode:2007ASPC..361..454K.
↑ Mikulášek, Z.; et al. (april 2008), "The record-breaking rotational deceleration of the He strong CP star HD 37776 (V901 Ori)", Contributions of the Astronomical Observatory Skalnaté Pleso, 38 (2): 429−430, arXiv:0712.0524, Bibcode:2008CoSka..38..429M.
↑ Mikulášek, Z.; et al. (October 2011), "Surprising variations in the rotation of the chemically peculiar stars CU Virginis and V901 Orionis", Astronomy & Astrophysics, 534, id. L5, arXiv:1110.1104, Bibcode:2011A&A...534L...5M, doi:10.1051/0004-6361/201117784.
↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, hämtad 6 november 2025.
↑ Krtička, J.; et al. (2007), Romanyuk, I. I.; Kudryavtsev, D. O. (eds.), "The light variations of HD 37776 as a result of the uneven surface distribution of helium and silicon", Physics of Magnetic Stars. Proceedings of the International Conference, held in the Special Astrophysical Observatory of the Russian AS, August 28-31, 2006, pp. 310–314, arXiv:astro-ph/0703396, Bibcode:2007pms..conf..310K.
↑ Krtička, J.; et al. (augusti 2007), "The light variability of the helium strong star HD 37776 as a result of its inhomogeneous elemental surface distribution", Astronomy and Astrophysics, 470 (3): 1089–1098, arXiv:0706.2338, Bibcode:2007A&A...470.1089K, doi:10.1051/0004-6361:20066627.
↑ Kochukhov, Oleg; et al. (januari 2011), "The Extraordinary Complex Magnetic Field of the Helium-strong Star HD 37776", The Astrophysical Journal, 726 (1), id. 24, arXiv:1010.5500, Bibcode:2011ApJ...726...24K, doi:10.1088/0004-637X/726/1/24.

Vidare läsning

Monier, Richard (maj 2023), ”The Behavior of Bp He-strong Stars in the far UV-Paper I: HD 37776”, Research Notes of the AAS 7 (5): id. 89, doi:10.3847/2515-5172/acd253, Bibcode: 2023RNAAS...7...89M.
Mikulášek, Z. (juli 2008), ”The extremely rapid rotational braking of the magnetic helium-strong star HD 37776”, Astronomy and Astrophysics 485 (2): 585–597, doi:10.1051/0004-6361:20077794, Bibcode: 2008A&A...485..585M.
Mikulášek, Z. (mars 2007), Stefl, S., red., ”Light Variations and Angular Momentum Loss from the He-Strong Magnetic Chemically Peculiar Star HD 37776”, Active OB-Stars: Laboratories for Stellar and Circumstellar Physics. Proceedings of the conference held 29 August - 2 september, 2005 at Hokkai-Gakuen University, Sapporo, Japan., ASP Conference Series (San Francisco: Astronomical Society of the Pacific) 361: s. 466, Bibcode: 2007ASPC..361..466M.
Glagolevskij, Yu. V.; Gerth, E. (2001), Mathys, G., red., ”The Magnetic Model of HD 37776”, Magnetic Fields Across the Hertzsprung-Russell Diagram, ASP Conference Proceedings (San Francisco: Astronomical Society of the Pacific) 248: 337, ISBN 1-58381-088-9, Bibcode: 2001ASPC..248..337G.
Khokhlova, V. L. (mars 2000), ”Doppler-Zeeman Mapping of the Rapidly Rotating Magnetic CP Star HD37776”, Astronomy Letters 26 (3): 177–191, doi:10.1134/1.20380, Bibcode: 2000AstL...26..177K.
Romanyuk, I. I. (1998), ”Spectrum and magnetic variations of the remarkable helium-strong star HD 37776 I. Observations and data reduction.”, Bulletin of the Special Astrophysical Observatory 45: 93–104, Bibcode: 1998BSAO...45...93R.
Adelman, S. J. (October 1997), ”UVBY photometry of the magnetic chemically peculiar stars HD 37776, HR 2258, HR 6958, and 108 Aquarii”, Astronomy & Astrophysics Supplement Series 125: 65–70, doi:10.1051/aas:1997211, Bibcode: 1997A&AS..125...65A.
Bohlender, D. A.; Landstreet, J. D. (september 1989), ”The Magnetic Field Geometry of the Helium-Strong Star HD 37776”, Bulletin of the American Astronomical Society 21: 1198, Bibcode: 1989BAAS...21.1198B.
Bohlender, D. A.; Landstreet, J. D. (oktober 1986), ”Spectral variations in the pecular helium-strong star HD 37776”, Journal of the Royal Astronomical Society of Canada 80 (5): 279–280, Bibcode: 1986JRASC..80..279B.
Adelman, S. J.; Pyper, D. M. (november 1985), ”Spectrophotometry of peculiar B and A stars. XVIII. The helium rich variable stars HR 1890, sigma Orionis E and HD 37776.”, Astronomy and Astrophysics, Supplement Series 62: 279–290, Bibcode: 1985A&AS...62..279A.

Externa länkar

https://www.universeguide.com/star/26742/v901orionis

[A-1] 1 2 3 4 5 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.

[B-2] 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875. Gaia DR3 record for this source at VizieR.

[C-3] 1 2 3 4 Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085. V901 Ori data

[E-4] 1 2 Houk, N.; Smith-Moore, M. (1988), Declinations -26°.0 to -12°.0, Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars, vol. 4, Bibcode:1988mcts.book.....H.

[F-5] 1 2 Jönsson, Henrik; et al. (17 augusti 2020), "APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South", The Astronomical Journal, 160 (3), American Astronomical Society: 120, arXiv:2007.05537, Bibcode:2020AJ....160..120J, doi:10.3847/1538-3881/aba592, ISSN 0004-6256.

[G-6] 1 2 3 4 5 6 7 Shultz, M. E.; et al. (juni 2022), "MOBSTER - VI. The crucial influence of rotation on the radio magnetospheres of hot stars", Monthly Notices of the Royal Astronomical Society, 513 (1): 1429–1448, arXiv:2201.05512, Bibcode:2022MNRAS.513.1429S, doi:10.1093/mnras/stac136.

[H-7] 1 2 Yu, Jie; et al. (2023), "Revised Extinctions and Radii for 1.5 Million Stars Observed by APOGEE, GALAH, and RAVE", The Astrophysical Journal Supplement Series, 264 (2): 41, arXiv:2206.00046, Bibcode:2023ApJS..264...41Y, doi:10.3847/1538-4365/acabc8

[D-8] 1 2 Shultz, M. E.; et al. (2019), "The magnetic early B-type stars - III. A main-sequence magnetic, rotational, and magnetospheric biography", Monthly Notices of the Royal Astronomical Society, 490 (1): 274, arXiv:1909.02530, Bibcode:2019MNRAS.490..274S, doi:10.1093/mnras/stz2551.

[J-9] 1 2 3 4 Mikulášek, Z.; et al. (november 2020), "What's New with Landstreet's Star HD 37776 (V901 Ori)?", in Wade, Gregg; et al. (eds.), Stellar Magnetism: A Workshop in Honour of the Career and Contributions of John D. Landstreet, held 8-11 July 2019 in London, Canada, Proceedings of the Polish Astronomical Society, vol. 11, pp. 46–53, arXiv:1912.04121, Bibcode:2020pase.conf...46M, ISBN 978-83-950430-9-3.

[SIMBAD-10] ttps://simbad.cds.unistra.fr/simbad/sim-id?Ident=V901+Ori. Hämtad 2026-03-26.

[K-11] "V901 Ori", SIMBAD, Centre de données astronomiques de Strasbourg, hämtad 2025-11-03.

[R-12] 1 2 Semenko, Eugene; et al. (september 2022), "Spectropolarimetry of magnetic Chemically Peculiar stars in the Orion OB1 association", Monthly Notices of the Royal Astronomical Society, 515 (1): 998–1011, arXiv:2207.00337, Bibcode:2022MNRAS.515..998S, doi:10.1093/mnras/stac1864.

[I-13] Román-Zúñiga, Carlos G.; et al. (February 2023), "Stellar Properties for a Comprehensive Collection of Star-forming Regions in the SDSS APOGEE-2 Survey", The Astronomical Journal, 165 (2), id. 51, arXiv:2211.09217, Bibcode:2023AJ....165...51R, doi:10.3847/1538-3881/aca3a4.

[M-14] Groote, D.; Kaufmann, J. P. (1981), "The helium-rich variable star HD 37776", Chemically peculiar stars of the upper main sequence; International Conference on Astrophysics, 23rd, Liege, Belgium, June 23-26, 1981, Reports. (A82-37717 18-39), vol. 23, Liege: Universite de Liege, pp. 435–438, Bibcode:1981LIACo..23..435G.

[N-15] Thompson, I. B.; Landstreet, J. D. (February 1985), "The extraordinary magnetic variation of the helium-strong star HD 37776 : a quadrupole field configuration.", Astrophysical Journal, 289: L9–L13, Bibcode:1985ApJ...289L...9T, doi:10.1086/184424.

[O-16] Krtička, J.; et al. (March 2007), Stefl, S.; et al. (eds.), "The Nature of Light Variations of the Helium Strong Chemically Peculiar Star HD 37776", Active OB-Stars: Laboratories for Stellar and Circumstellar Physics. Proceedings of the conference held 29 August - 2 september, 2005 at Hokkai-Gakuen University, Sapporo, Japan, ASP Conference Series, vol. 361, San Francisco: Astronomical Society of the Pacific, p. 454, arXiv:astro-ph/0509751, Bibcode:2007ASPC..361..454K.

[P-17] Mikulášek, Z.; et al. (april 2008), "The record-breaking rotational deceleration of the He strong CP star HD 37776 (V901 Ori)", Contributions of the Astronomical Observatory Skalnaté Pleso, 38 (2): 429−430, arXiv:0712.0524, Bibcode:2008CoSka..38..429M.

[Q-18] Mikulášek, Z.; et al. (October 2011), "Surprising variations in the rotation of the chemically peculiar stars CU Virginis and V901 Orionis", Astronomy & Astrophysics, 534, id. L5, arXiv:1110.1104, Bibcode:2011A&A...534L...5M, doi:10.1051/0004-6361/201117784.

[L-19] MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, hämtad 6 november 2025.

[S-20] Krtička, J.; et al. (2007), Romanyuk, I. I.; Kudryavtsev, D. O. (eds.), "The light variations of HD 37776 as a result of the uneven surface distribution of helium and silicon", Physics of Magnetic Stars. Proceedings of the International Conference, held in the Special Astrophysical Observatory of the Russian AS, August 28-31, 2006, pp. 310–314, arXiv:astro-ph/0703396, Bibcode:2007pms..conf..310K.

[T-21] Krtička, J.; et al. (augusti 2007), "The light variability of the helium strong star HD 37776 as a result of its inhomogeneous elemental surface distribution", Astronomy and Astrophysics, 470 (3): 1089–1098, arXiv:0706.2338, Bibcode:2007A&A...470.1089K, doi:10.1051/0004-6361:20066627.

[U-22] Kochukhov, Oleg; et al. (januari 2011), "The Extraordinary Complex Magnetic Field of the Helium-strong Star HD 37776", The Astrophysical Journal, 726 (1), id. 24, arXiv:1010.5500, Bibcode:2011ApJ...726...24K, doi:10.1088/0004-637X/726/1/24.