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Rigel


Rigel, also designated Beta Orionis (β Orionis, abbreviated Beta Ori, β Ori), is usually the 7th brightest star in the night sky and the brightest star in the constellation of Orion, though periodically it is outshone within the constellation by the variable red supergiant Betelgeuse. With a visual magnitude of 0.13, it is a highly luminous star some 863 light-years distant from Earth.

Rigel
Map of the constellation Orion
Red circle.svg
Rigel in the constellation Orion (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Orion
A
Right ascension 05h 14m 32.27210s[1]
Declination −08° 12′ 05.8981″[1]
Apparent magnitude (V) 0.13[2] (0.05 - 0.18[3])
B
Right ascension 05h 14m 32.049s[4]
Declination −08° 12′ 14.78″[4]
Apparent magnitude (V) 6.67[5]
Characteristics
A
Evolutionary stage Blue supergiant
Spectral type B8 Ia[6]
U−B color index −0.66[7]
B−V color index −0.03[7]
Variable type Alpha Cygni[8]
B
Evolutionary stage Spectroscopic binary
Spectral type B9V + B9V[9]
U−B color index −0.66[7]
B−V color index −0.03[7]
Variable type Alpha Cygni[8]
Astrometry
Radial velocity (Rv)17.8±0.4[10] km/s
Proper motion (μ) RA: +1.31[1] mas/yr
Dec.: +0.50[1] mas/yr
Parallax (π)3.78 ± 0.34[1] mas
Distance860 ± 80 ly
(260 ± 20 pc)
Absolute magnitude (MV)-7.84[11]
Orbit[5]
PrimaryBa
CompanionBb
Period (P)9.860 days
Eccentricity (e)0.1
Semi-amplitude (K1)
(primary)
25.0 km/s
Semi-amplitude (K2)
(secondary)
32.6 km/s
Details
A
Mass23[12] M
Radius78.9±7.4[13], 115[14] R
Diameter78.9±7.4[13], 115[14] D
Luminosity (bolometric)1.20+0.25
−0.21
×105[13] L
Surface gravity (log g)1.75±0.10[12] cgs
Temperature12100±150[12] K
Metallicity [Fe/H]−0.06±0.10[6] dex
Rotational velocity (v sin i)25±3[12] km/s
Age8±1[6] Myr
Ba
Mass3.84[9] M
Bb
Mass2.94[9] M
Other designations
Rigel, Algebar, Elgebar, β Ori, 19 Ori, HD 34085, HR 1713, HIP 24436, SAO 131907, BD-08° 1063 [15]
Database references
SIMBADdata

The star as seen from Earth is actually a multiple star system of three to five stars, the primary star, Rigel A being a blue-white supergiant which is estimated to be anywhere from 120,000 to 279,000 times as luminous as the Sun, depending on the method used to calculate its properties. It has exhausted its core of hydrogen and swollen to between 78,9 to 115 times the Sun's diameter. Rigel is classified as an Alpha Cygni variable. A companion, Rigel B, is 500 times fainter than the supergiant Rigel A and visible only with a telescope. Rigel B is itself a spectroscopic binary system, consisting of two main sequence blue-white stars both having a spectral type B9V that are estimated to be 3.9 and 2.9 times as massive as the Sun respectively, Rigel B also appears to have a very close visual companion Rigel C which is almost identical in appearance. Rigel is visible basically anywhere on Earth due to its proximity to the equator. The peoples of Icons-flag-nz.png New Zealand refer to it as Puanga and use it to celebrate their new year. In Icons-flag-jp.png Japan, the Minamoto or Genji clan chose Rigel and its white color as its symbol, calling the star Genji-boshi (源氏星), while the Taira or Heike clan adopted Betelgeuse and its red color. The two powerful families fought in a war; the stars seen as facing each other off and only kept apart by Orion's belt.[16][17][18]

PropertiesEdit

 
Rigel's place at top center on the Hertzsprung-Russell diagram

Moravveji et al and colleagues calculate a luminosity for Rigel A being 120,000 times that of the Sun's.[13] Its surface temperature is around 12,100 K. The interferometer-measured angular diameter of this star, after correction for limb darkening, is 2.75±0.01 milliarcseconds.[19] At its estimated distance, this yields a size of about 78.9 times the Sun's diameter.[13] On the other hand, Norbert Przybilla et al and colleagues used atmospheric modelling in 2006 to come up with a distance of 360 ± 40 parsecs (1,170 ± 130 light-years). They calculated it to be around 218,000 times as luminous as the Sun, and have around 21 ± 3 solar masses in mass and 109 ± 12 times its diameter.[6] The CMFGEN code is an atmosphere code used to determine the properties of massive stars from analysing their spectrum and atmosphere. Analysis of Rigel using this method yields a luminosity 279,000 times that of the Sun, a radius 115 times that of the Sun, and a stellar wind velocity of over 671,080 miles per hour.[14]

Rigel A is a blue supergiant that has exhausted burning the hydrogen fuel in its core and left the main sequence, expanding and brightening as it progresses across the Hertzsprung–Russell diagram. Przybilla estimated that it has lost around 3 solar masses since beginning life as a star of 24 ± 3 solar masses 7 to 9 million years ago.[6] It will become a red supergiant and eventually end its stellar life by exploding as a type II supernova, in the process flinging out material that will serve to create future generations of stars.[8] It is one of the closest known potential supernova candidates to the Earth.[13]

See alsoEdit

ReferencesEdit

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (November 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. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237: 0. Bibcode 2002yCat.2237....0D.
  3. Guinan, E. F.; Eaton, J. A.; Wasatonic, R.; Stewart, H.; Engle, S. G.; McCook, G. P. (2010). "Times-Series Photometry & Spectroscopy of the Bright Blue Supergiant Rigel: Probing the Atmosphere and Interior of a SN II Progenitor". Proceedings of the International Astronomical Union 5: 359. Bibcode 2010HiA....15..359G. doi:10.1017/S1743921310009798.
  4. 4.0 4.1 DENIS Consortium (2005). "VizieR Online Data Catalog: The DENIS database (DENIS Consortium, 2005)". VizieR On-line Data Catalog: B/denis. Originally published in: 2005yCat.2263....0T 1. Bibcode 2005yCat....102002D.
  5. 5.0 5.1 Sanford, Roscoe F. (1942). "The Spectrographic Orbit of the Companion to Rigel". Astrophysical Journal 95: 421. Bibcode 1942ApJ....95..421S. doi:10.1086/144412.
  6. 6.0 6.1 6.2 6.3 6.4 Przybilla, N. et al. (January 2006). "Quantitative spectroscopy of BA-type supergiants". Astronomy and Astrophysics 445 (3): 1099–1126. arXiv:astro-ph/0509669. Bibcode 2006A&A...445.1099P. doi:10.1051/0004-6361:20053832.
  7. 7.0 7.1 7.2 7.3 Nicolet, B. (1978). "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System". Astronomy and Astrophysics Supplement Series 34: 1–49. Bibcode 1978A&AS...34....1N.
  8. 8.0 8.1 8.2 Moravveji, Ehsan; Moya, Andres; Guinan, Edward F. (April 2012). "Asteroseismology of the nearby SN-II Progenitor: Rigel. Part II. ε-mechanism Triggering Gravity-mode Pulsations?". The Astrophysical Journal 749 (1): 74–84. arXiv:1202.1836. Bibcode 2012ApJ...749...74M. doi:10.1088/0004-637X/749/1/74.
  9. 9.0 9.1 9.2 Tokovinin, A. A. (1997). "MSC - a catalogue of physical multiple stars". Astronomy & Astrophysics Supplement Series 124: 75. Bibcode 1997A&AS..124...75T. doi:10.1051/aas:1997181.
  10. Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. arXiv:1606.08053. Bibcode 2006AstL...32..759G. doi:10.1134/S1063773706110065.
  11. Cite error: Invalid <ref> tag; no text was provided for refs named schultz
  12. 12.0 12.1 12.2 12.3 Przybilla, N. (2010). "Mixing of CNO-cycled matter in massive stars". Astronomy and Astrophysics 517: A38. arXiv:1005.2278. Bibcode 2010A&A...517A..38P. doi:10.1051/0004-6361/201014164.
  13. 13.0 13.1 13.2 13.3 13.4 Moravveji, Ehsan; Guinan, Edward F.; Shultz, Matt; Williamson, Michael H.; Moya, Andres (March 2012). "Asteroseismology of the nearby SN-II Progenitor: Rigel. Part I. The MOST High-precision Photometry and Radial Velocity Monitoring". The Astrophysical Journal 747 (1): 108–115. arXiv:1201.0843. Bibcode 2012ApJ...747..108M. doi:10.1088/0004-637X/747/2/108.
  14. 14.0 14.1 =Chesneau, O.; Kaufer, A.; Stahl, O.; Colvinter, C.; Spang, A.; Dessart, L.; Prinja, R.; Chini, R. (2014). "The variable stellar wind of Rigel probed at high spatial and spectral resolution". Astronomy & Astrophysics 566: 18. arXiv:1405.0907. Bibcode 2014A&A...566A.125C. doi:10.1051/0004-6361/201322894. A125.
  15. Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  16. Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  17. "Daijirin" p. 815 ISBN 978-4-385-13902-9
  18. Hōei Nojiri "Shin seiza jyunrei" p. 19 ISBN 978-4-12-204128-8
  19. Aufdenberg, J. P. (2008). "Limb Darkening: Getting Warmer". The Power of Optical/IR Interferometry. Eso Astrophysics Symposia 1 (1): 71–82. Bibcode 2008poii.conf...71A. doi:10.1007/978-3-540-74256-2_8. ISBN 978-3-540-74253-1.
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