FU Orionis

This article is about the particular star. For the type of variable stars named after this star, see FU Orionis stars.
FU Orionis

The blue band light curve for FU Orionis, adapted from Clarke et al. (2005).[1] The inset plot, adapted from Siwak, et al. (2013),[2] illustrates the short timescale variability.
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Orion
Right ascension 05h 45m 22.362s[3]
Declination +09° 04′ 12.31″[3]
Apparent magnitude (V) 8.94[3]
Characteristics
Spectral type uncertain + K5+2
−1[4]
B−V color index 1.41[3]
Variable type FU Ori[5]
Astrometry
Proper motion (μ) RA: 2.218 ± 0.079[6] mas/yr
Dec.: -2.834 ± 0.065[6] mas/yr
Parallax (π)2.4029 ± 0.0497 mas[6]
Distance1,360 ± 30 ly
(416 ± 9 pc)
Details
FU Orionis north
Mass0.6[7] M☉
Radius10.42[8] R☉
Temperature5095.1[8] K
FU Orionis south
Mass1.2[4] M☉
Temperature4350[4] K
Age~2[4] Myr
Other designations
FU Ori, BD+09 5427.[3]
Database references
SIMBADdata

FU Orionis is a variable and binary star[9] system in the constellation of Orion, that in 1937 rose in apparent visual magnitude from 16.5 to 9.6, and has since been around magnitude 9.[10][3] The name FU Orionis is a variable star designation in the Argelander system, which are assigned sequentially as new variables are discovered.[11] FU Orionis is about 1,360 light years distant and is associated with the molecular cloud Barnard 35.[6][12]

For a long time this variable was considered unique, but in 1970 a similar star, V1057 Cygni, was discovered, and a number of additional examples have been discovered since then. These stars constitute the FU Orionis class of variable stars, GCVS type FU, often nicknamed FUors. These stars are pre–main sequence stars which display an extreme change in magnitude and spectral type.

  1. ^ Cite error: The named reference Clarke2005 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Siwak2013 was invoked but never defined (see the help page).
  3. ^ a b c d e f "V* FU Ori". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved December 8, 2008.
  4. ^ a b c d Cite error: The named reference Beck et al was invoked but never defined (see the help page).
  5. ^ FU Ori, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars Archived 2017-06-20 at the Wayback Machine, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line December 8, 2008.
  6. ^ a b c d Gaia Collaboration (2018-08-01). "Gaia Data Release 2 - Summary of the contents and survey properties". Astronomy & Astrophysics. 616: A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. ISSN 0004-6361. S2CID 49211658.
  7. ^ Cite error: The named reference Pérez et al was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  9. ^ Wang, Hongchi; Apai, Dániel; Henning, Thomas; Pascucci, Ilaria (January 2004). "FU Orionis: A Binary Star?". Astrophysical Journal Letters. 601 (1): L83–L86. arXiv:astro-ph/0311606. Bibcode:2004ApJ...601L..83W. doi:10.1086/381705. ISSN 0004-637X. S2CID 17793369.
  10. ^ AAVSO: FU Orionis
  11. ^ Cite error: The named reference Townley1915 was invoked but never defined (see the help page).
  12. ^ Smith, H. A.; Thronson, H. A.; Lada, C. J.; Harper, D. A.; Loewenstein, R. F.; Smith, J. (July 1982). "Far-infrared observations of FU Ori". Astrophysical Journal. 258: 170–176. Bibcode:1982ApJ...258..170S. doi:10.1086/160065. ISSN 0004-637X.