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Sigma Sagittarii

January 01, 1970

Sigma Sagittarii, Latinized from σ Sagittarii; formally named Nunki /ˈnʌŋki/,[13][14] is the second-brightest star in the constellation of Sagittarius. It has an apparent magnitude of +2.05,[3] making it readily visible to the naked eye. The distance to this star, determined using parallax measurements from the Hipparcos astrometry satellite,[15] yields a value of approximately 228 light-years (70 parsecs) from the Sun.[1][2]

Sigma Sagittarii
Location of σ Sagittarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Sagittarius
Right ascension 18h 55m 15.92650s[1][2]
Declination –26° 17′ 48.2068″[1][2]
Apparent magnitude (V) 2.05[3]
Characteristics
Spectral type B2.5 V[4]
U−B color index –0.761[5]
B−V color index –0.204[5]
Astrometry
Radial velocity (Rv)–11.2[3] km/s
Proper motion (μ) RA: +15.14[1][2] mas/yr
Dec.: –53.43[1][2] mas/yr
Parallax (π)14.32 ± 0.29 mas[1][2]
Distance228 ± 5 ly
(70 ± 1 pc)
Absolute magnitude (MV)−2.17[6]
Details
Mass7.8±0.2[7] M☉
Radius4.5[8] R☉
Luminosity3,300[9] L☉
Temperature18,890[9] K
Rotational velocity (v sin i)165[10] km/s
Age31.4±0.4[7] Myr
Other designations
Nunki, Sadira[11][12], σ Sgr, Sigma Sgr, 34 Sagittarii, CPD−27  5241, FK5 706, GC 25941, HD 175191, HIP 92855, HR 7121, SAO 187448, PPM 269078, CCDM J18552-2618A, WDS J18553-2618Aa,Ab
Database references
SIMBADdata

Properties edit

Sigma Sagittarii has a spectrum matching a stellar classification of B2.5 V,[4] which indicates this is a B-type main-sequence star. Its total luminosity is 3300[16] times that of the Sun while it has a surface temperature of 18,890 K.[9] X-ray emission has been detected from this star, which has an estimated X-ray luminosity of 1.2 × 1028 erg s−1.[17]

It has a 10th magnitude optical companion located 5.2 arcminutes away.[18]

It is 3.45 degrees south of the ecliptic, so it can be occulted by the Moon and rarely by planets. The last occultation by a planet took place on November 17, 1981, when it was occulted by Venus.[19] This is the brightest star that can be principally occulted by an exterior planet between 5000 BC and 5000 AD. However, only Mars can do this, and only rarely; the last time was on September 3, 423.[citation needed]

Nomenclature edit

σ Sagittarii (Latinised to Sigma Sagittarii) is the star's Bayer designation. In his Uranometria star atlas, Johann Bayer placed this star in the fourth magnitude class, although it is a second-magnitude star by modern measurements.[citation needed]

It bore the traditional name of Nunki, which was an Assyrian or Babylonian name recovered by archaeologists and made public by R. H. Allen.[20] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[21] to catalogue and standardize proper names for stars. The WGSN approved the name Nunki for this star on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.[14]

This star, together with :

Zeta Sagittarii and Pi Sagittarii may have been the Akkadian Gu-shi-rab‑ba, the Yoke of the Sea.[23]

In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Thanih al Sadirah, which was translated into Latin as Secunda τού al Sadirah, meaning second returning ostrich.[24]

In Chinese, 斗 (Dǒu), meaning Dipper, refers to an asterism consisting of Sigma Sagittarii, Phi Sagittarii, Lambda Sagittarii, Mu Sagittarii, Tau Sagittarii and Zeta Sagittarii. Consequently, the Chinese name for Sigma Sagittarii itself is 斗宿四 (Dǒu Xiù sì, English: the Fourth Star of Dipper.)[25]

References edit

  1. ^ a b c d e f Perryman, M. A. C.; Lindegren, L.; Kovalevsky, J.; Hoeg, E.; Bastian, U.; Bernacca, P. L.; Crézé, M.; Donati, F.; Grenon, M.; Grewing, M.; Van Leeuwen, F.; Van Der Marel, H.; Mignard, F.; Murray, C. A.; Le Poole, R. S.; Schrijver, H.; Turon, C.; Arenou, F.; Froeschlé, M.; Petersen, C. S. (July 1997), "The Hipparcos Catalogue", Astronomy and Astrophysics, 323: L49–L52, Bibcode:1997A&A...323L..49P
  2. ^ a b c d e f van Leeuwen, Floor (13 August 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. eISSN 1432-0746. ISSN 0004-6361.
  3. ^ a b c Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veröff. Astron. Rechen-Inst. Heidelb, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W
  4. ^ a b Houk, Nancy (1979), "Michigan catalogue of two-dimensional spectral types for the HD stars", Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume_3. Declinations -40_ƒ0 to -26_ƒ0, 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1982mcts.book.....H
  5. ^ a b Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168
  6. ^ 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, S2CID 119257644.
  7. ^ a b Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873
  8. ^ Underhill, A. B.; et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society, 189 (3): 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601
  9. ^ a b c Zorec, J.; et al. (July 2009), "Fundamental parameters of B supergiants from the BCD system. I. Calibration of the (λ_1, D) parameters into Teff", Astronomy and Astrophysics, 501 (1): 297–320, arXiv:0903.5134, Bibcode:2009A&A...501..297Z, doi:10.1051/0004-6361/200811147, S2CID 14969137
  10. ^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590
  11. ^ Paul Kunitzsch [in German] (1959). Arabische Sternnamen in Europa. Wiesbaden: Otto Harrassowitz. p. 137. Retrieved 2020-08-30.
  12. ^ Robert Burnham, Jr. (1978). Burnham's Celestial Handbook: An Observer's Guide to the Universe Beyond the Solar System. Vol. 3. New York: Dover Publications Inc. p. 1566. ISBN 9780486318035. Retrieved 2020-08-30.
  13. ^ Davis, George A. (1944). "The pronunciations, derivations, and meanings of a selected list of star names". Popular Astronomy. 52: 26. Bibcode:1944PA.....52....8D.
  14. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  15. ^ Perryman, Michael (2010), The Making of History's Greatest Star Map, Astronomers’ Universe, Heidelberg: Springer-Verlag, Bibcode:2010mhgs.book.....P, doi:10.1007/978-3-642-11602-5, ISBN 978-3-642-11601-8
  16. ^ James B. Kaler, "NUNKI (Sigma Sagatarii)", Stars, University of Illinois, retrieved 2012-01-31
  17. ^ Cassinelli, J. P.; et al. (February 1994), "X-ray emission from near-main-sequence B stars", Astrophysical Journal, Part 1, 421 (2): 705–717, Bibcode:1994ApJ...421..705C, doi:10.1086/173683
  18. ^ 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.
  19. ^ Können, G. P.; Van Maanen, J. (April 1981). "Planetary occultations of bright stars". Journal of the British Astronomical Association. 91: 148–157. Bibcode:1981JBAA...91..148K.
  20. ^ Allen, Richard Hinckley, Star Names, their lore and meaning, p. 359
  21. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
  22. ^ "Teapot". constellation-guide.com. Retrieved 2017-05-13.
  23. ^ a b Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc. p. 355. ISBN 0-486-21079-0. Retrieved 2012-09-04.
  24. ^ Knobel, E. B. (June 1895). "Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket". Monthly Notices of the Royal Astronomical Society. 55 (8): 430. Bibcode:1895MNRAS..55..429K. doi:10.1093/mnras/55.8.429.
  25. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 11 日

January 01, 1970
sigma, sagittarii, latinized, from, sagittarii, formally, named, nunki, second, brightest, star, constellation, sagittarius, apparent, magnitude, making, readily, visible, naked, distance, this, star, determined, using, parallax, measurements, from, hipparcos,. Sigma Sagittarii Latinized from s Sagittarii formally named Nunki ˈ n ʌ ŋ k i 13 14 is the second brightest star in the constellation of Sagittarius It has an apparent magnitude of 2 05 3 making it readily visible to the naked eye The distance to this star determined using parallax measurements from the Hipparcos astrometry satellite 15 yields a value of approximately 228 light years 70 parsecs from the Sun 1 2 Sigma SagittariiLocation of s Sagittarii circled Observation dataEpoch J2000 Equinox J2000 Constellation Sagittarius Right ascension 18h 55m 15 92650s 1 2 Declination 26 17 48 2068 1 2 Apparent magnitude V 2 05 3 Characteristics Spectral type B2 5 V 4 U B color index 0 761 5 B V color index 0 204 5 AstrometryRadial velocity Rv 11 2 3 km sProper motion m RA 15 14 1 2 mas yr Dec 53 43 1 2 mas yrParallax p 14 32 0 29 mas 1 2 Distance228 5 ly 70 1 pc Absolute magnitude MV 2 17 6 DetailsMass7 8 0 2 7 M Radius4 5 8 R Luminosity3 300 9 L Temperature18 890 9 KRotational velocity v sin i 165 10 km sAge31 4 0 4 7 Myr Other designationsNunki Sadira 11 12 s Sgr Sigma Sgr 34 Sagittarii CPD 27 5241 FK5 706 GC 25941 HD 175191 HIP 92855 HR 7121 SAO 187448 PPM 269078 CCDM J18552 2618A WDS J18553 2618Aa Ab Database referencesSIMBADdataProperties editSigma Sagittarii has a spectrum matching a stellar classification of B2 5 V 4 which indicates this is a B type main sequence star Its total luminosity is 3300 16 times that of the Sun while it has a surface temperature of 18 890 K 9 X ray emission has been detected from this star which has an estimated X ray luminosity of 1 2 1028 erg s 1 17 It has a 10th magnitude optical companion located 5 2 arcminutes away 18 It is 3 45 degrees south of the ecliptic so it can be occulted by the Moon and rarely by planets The last occultation by a planet took place on November 17 1981 when it was occulted by Venus 19 This is the brightest star that can be principally occulted by an exterior planet between 5000 BC and 5000 AD However only Mars can do this and only rarely the last time was on September 3 423 citation needed Nomenclature edits Sagittarii Latinised to Sigma Sagittarii is the star s Bayer designation In his Uranometria star atlas Johann Bayer placed this star in the fourth magnitude class although it is a second magnitude star by modern measurements citation needed It bore the traditional name of Nunki which was an Assyrian or Babylonian name recovered by archaeologists and made public by R H Allen 20 In 2016 the International Astronomical Union organized a Working Group on Star Names WGSN 21 to catalogue and standardize proper names for stars The WGSN approved the name Nunki for this star on 21 August 2016 and it is now so included in the List of IAU approved Star Names 14 This star together with Gamma Sagittarii Delta Sagittarii Epsilon Sagittarii Zeta Sagittarii Lambda Sagittarii Tau Sagittarii and Phi Sagittarii comprised the Teapot asterism 22 Phi Sagittarii Zeta Sagittarii Chi Sagittarii and Tau Sagittarii were the Arabic Al Naʽam al Ṣadirah النعم السادرة the Returning Ostriches 23 Zeta Sagittarii and Pi Sagittarii may have been the Akkadian Gu shi rab ba the Yoke of the Sea 23 In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket this star was designated Thanih al Sadirah which was translated into Latin as Secunda toy al Sadirah meaning second returning ostrich 24 In Chinese 斗 Dǒu meaning Dipper refers to an asterism consisting of Sigma Sagittarii Phi Sagittarii Lambda Sagittarii Mu Sagittarii Tau Sagittarii and Zeta Sagittarii Consequently the Chinese name for Sigma Sagittarii itself is 斗宿四 Dǒu Xiu si English the Fourth Star of Dipper 25 References edit a b c d e f Perryman M A C Lindegren L Kovalevsky J Hoeg E Bastian U Bernacca P L Creze M Donati F Grenon M Grewing M Van Leeuwen F Van Der Marel H Mignard F Murray C A Le Poole R S Schrijver H Turon C Arenou F Froeschle M Petersen C S July 1997 The Hipparcos Catalogue Astronomy and Astrophysics 323 L49 L52 Bibcode 1997A amp A 323L 49P a b c d e f van Leeuwen Floor 13 August 2007 Validation of the new Hipparcos reduction Astronomy amp Astrophysics 474 2 653 664 arXiv 0708 1752 Bibcode 2007A amp A 474 653V doi 10 1051 0004 6361 20078357 eISSN 1432 0746 ISSN 0004 6361 a b c Wielen R et al 1999 Sixth Catalogue of Fundamental Stars FK6 Part I Basic fundamental stars with direct solutions Veroff Astron Rechen Inst Heidelb 35 35 Astronomisches Rechen Institut Heidelberg 1 Bibcode 1999VeARI 35 1W a b Houk Nancy 1979 Michigan catalogue of two dimensional spectral types for the HD stars Michigan Catalogue of Two dimensional Spectral Types for the HD Stars Volume 3 Declinations 40 ƒ0 to 26 ƒ0 3 Ann Arbor Michigan Dept of Astronomy University of Michigan Bibcode 1982mcts book H a b Gutierrez Moreno Adelina Moreno Hugo June 1968 A photometric investigation of the Scorpio Centaurus association Astrophysical Journal Supplement 15 459 Bibcode 1968ApJS 15 459G doi 10 1086 190168 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 S2CID 119257644 a b Tetzlaff N Neuhauser R Hohle M M January 2011 A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun Monthly Notices of the Royal Astronomical Society 410 1 190 200 arXiv 1007 4883 Bibcode 2011MNRAS 410 190T doi 10 1111 j 1365 2966 2010 17434 x S2CID 118629873 Underhill A B et al November 1979 Effective temperatures angular diameters distances and linear radii for 160 O and B stars Monthly Notices of the Royal Astronomical Society 189 3 601 605 Bibcode 1979MNRAS 189 601U doi 10 1093 mnras 189 3 601 a b c Zorec J et al July 2009 Fundamental parameters of B supergiants from the BCD system I Calibration of the l 1 D parameters into Teff Astronomy and Astrophysics 501 1 297 320 arXiv 0903 5134 Bibcode 2009A amp A 501 297Z doi 10 1051 0004 6361 200811147 S2CID 14969137 Abt Helmut A Levato Hugo Grosso Monica July 2002 Rotational Velocities of B Stars The Astrophysical Journal 573 1 359 365 Bibcode 2002ApJ 573 359A doi 10 1086 340590 Paul Kunitzsch in German 1959 Arabische Sternnamen in Europa Wiesbaden Otto Harrassowitz p 137 Retrieved 2020 08 30 Robert Burnham Jr 1978 Burnham s Celestial Handbook An Observer s Guide to the Universe Beyond the Solar System Vol 3 New York Dover Publications Inc p 1566 ISBN 9780486318035 Retrieved 2020 08 30 Davis George A 1944 The pronunciations derivations and meanings of a selected list of star names Popular Astronomy 52 26 Bibcode 1944PA 52 8D a b Naming Stars IAU org Retrieved 16 December 2017 Perryman Michael 2010 The Making of History s Greatest Star Map Astronomers Universe Heidelberg Springer Verlag Bibcode 2010mhgs book P doi 10 1007 978 3 642 11602 5 ISBN 978 3 642 11601 8 James B Kaler NUNKI Sigma Sagatarii Stars University of Illinois retrieved 2012 01 31 Cassinelli J P et al February 1994 X ray emission from near main sequence B stars Astrophysical Journal Part 1 421 2 705 717 Bibcode 1994ApJ 421 705C doi 10 1086 173683 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 Konnen G P Van Maanen J April 1981 Planetary occultations of bright stars Journal of the British Astronomical Association 91 148 157 Bibcode 1981JBAA 91 148K Allen Richard Hinckley Star Names their lore and meaning p 359 IAU Working Group on Star Names WGSN International Astronomical Union retrieved 22 May 2016 Teapot constellation guide com Retrieved 2017 05 13 a b Allen R H 1963 Star Names Their Lore and Meaning Reprint ed New York Dover Publications Inc p 355 ISBN 0 486 21079 0 Retrieved 2012 09 04 Knobel E B June 1895 Al Achsasi Al Mouakket on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket Monthly Notices of the Royal Astronomical Society 55 8 430 Bibcode 1895MNRAS 55 429K doi 10 1093 mnras 55 8 429 in Chinese AEEA Activities of Exhibition and Education in Astronomy 天文教育資訊網 2006 年 5 月 11 日 Retrieved from https en wikipedia org w index php title Sigma Sagittarii amp oldid 1191747922, wikipedia, wiki, book, books, library,

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