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Alpha Gruis

May 21, 2023

"Alnair" redirects here. For the star in Centaurus, see Zeta Centauri.

Alpha Gruis is the brightest star in the southern constellation of Grus. It is officially named Alnair;[1] Alpha Gruis is the star's Bayer designation, which is Latinized from α Gruis and abbreviated α Gru. With an magnitude of 1.7, it is one of the brightest stars in the sky and one of the fifty-eight stars selected for celestial navigation. Alpha Gruis is a single, B-type main-sequence star located at a distance of 31 pc.

Alpha Gruis
Location of α Gruis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Grus
Pronunciation /ælˈnɛər/[1]
Right ascension 22h 08m 13.98473s[2]
Declination –46° 57′ 39.5078″[2]
Apparent magnitude (V) +1.74[3]
Characteristics
Spectral type B6 V[4]
U−B color index –0.47[3]
B−V color index –0.13[3]
Astrometry
Radial velocity (Rv)+11.8[5] km/s
Proper motion (μ) RA: +126.69[2] mas/yr
Dec.: −147.47[2] mas/yr
Parallax (π)32.29 ± 0.21 mas[2]
Distance101.0 ± 0.7 ly
(31.0 ± 0.2 pc)
Absolute magnitude (MV)−0.72[6]
Details
Mass4.0[7] M☉
Radius3.4[8] R☉
Luminosity520[9] L☉
Surface gravity (log g)3.76±0.11[10] cgs
Temperature13,920[11] K
Metallicity [Fe/H]−0.13±0.02[12] dex
Rotational velocity (v sin i)215[13] km/s
Age100[14] Myr
Other designations
Al Na'ir, α Gru, CD−47°14063, FK5 829, GJ 848.2, HD 209952, HIP 109268, HR 8425, SAO 230992[15]
Database references
SIMBADdata

Nomenclature

α Gruis (Latinised to Alpha Gruis) is the star's Bayer designation. (Its first depiction in a celestial atlas was in Johann Bayer's Uranometria of 1603.[16])

It bore the traditional name Alnair or Al Nair (sometimes Al Na'ir in lists of stars used by navigators),[17] from the Arabic al-nayyir "the bright one", itself derived from its Arabic name, al-nayyir min dhanab al-ḥūt (al-janūbiyy), "the bright one from the (southern) fish's tail" (see Aldhanab).[18] Confusingly, Alnair was also given as the proper name for Zeta Centauri in an astronomical ephemerides in the middle of the 20th century.[19] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[20] to catalog and standardize proper names for stars. The WGSN approved the name Alnair for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.[21]

Along with Beta Gruis, Delta Gruis, Theta Gruis, Iota Gruis, and Lambda Gruis, Alpha Gruis belonged to Piscis Austrinus in traditional Arabic astronomy.[22]

In Chinese, 鶴 (Hè), meaning Crane, refers to an asterism consisting of Alpha Gruis, Beta Gruis, Delta2 Gruis, Epsilon Gruis, Zeta Gruis, Eta Gruis, Iota Gruis, Theta Gruis, Mu1 Gruis and Delta Tucanae.[23] Consequently, Alpha Gruis itself is known as 鶴一 (Hè yī, English: First Star of the Crane).[24] The Chinese name gave rise to another English name, Ke.[25]

Properties

Alpha Gruis has a stellar classification of B6 V,[4] although some sources give it a classification of B7 IV.[26] The first classification indicates that this is a B-type star on the main sequence of stars that are generating energy through the thermonuclear fusion of hydrogen at the core. However, a luminosity class of 'IV' would suggest that this is a subgiant star; meaning the supply of hydrogen at its core is becoming exhausted and the star has started the process of evolving away from the main sequence. It has no known companions.[26]

The measured angular diameter of this star, after correcting for limb darkening, is 1.02 ± 0.07 mas.[8] At a parallax-measured distance of 101 light-years (31 parsecs) from Earth, this yields a physical size of 3.4 times the radius of the Sun.[27] It is rotating rapidly, with a projected rotational velocity of about 215 km/s providing a lower bound for the rate of azimuthal rotation along the equator.[13] This star has around four times the Sun's mass and is radiating roughly 520 times the luminosity of the Sun.[9]

The effective temperature of Alpha Gruis's outer envelope is 13,920 K,[11] giving it the blue-white hue characteristic of B-type stars.[28] The abundance of elements other than hydrogen and helium, what astronomers term the metallicity, is about 74% of the abundance in the Sun.[12]

Based on the estimated age and motion, it may be a member of the AB Doradus moving group that share a common motion through space. This group has an age of about 70 million years,[29] which is consistent with α Gruis's 100-million-year[14] estimated age (allowing for a margin of error). The space velocity components of this star in the Galactic coordinate system are [U, V, W] = [–7.0 ± 1.1, –25.6 ± 0.7, –15.5 ± 1.4] km/s.[29]

References

  1. ^ a b Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  2. ^ a b c d e 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. S2CID 18759600.
  3. ^ a b c Hoffleit, D.; Warren, W. H. Jr. "HR 8425, database entry". The Bright Star Catalogue (5th Revised (Preliminary) ed.). CDS. Retrieved 5 September 2015.
  4. ^ a b Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
  5. ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington: 0. Bibcode:1953GCRV..C......0W.
  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. ^ Malagnini, M. L.; Morossi, C. (November 1990). "Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars". Astronomy and Astrophysics Supplement Series. 85 (3): 1015–1019. Bibcode:1990A&AS...85.1015M.
  8. ^ a b Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005). "CHARM2: An updated Catalog of High Angular Resolution Measurements". Astronomy and Astrophysics. 431 (2): 773–777. Bibcode:2005A&A...431..773R. doi:10.1051/0004-6361:20042039.
  9. ^ a b McCarthy, K.; White, R. J. (June 2012). "The Sizes of the Nearest Young Stars". The Astronomical Journal. 143 (6): 134. arXiv:1201.6600. Bibcode:2012AJ....143..134M. doi:10.1088/0004-6256/143/6/134. S2CID 118538522.
  10. ^ Fitzpatrick, Edward L.; Massa, Derck (November 1999). "Determining the Physical Properties of the B Stars. I. Methodology and First Results". The Astrophysical Journal. 525 (2): 1011–1023. arXiv:astro-ph/9906257. Bibcode:1999ApJ...525.1011F. doi:10.1086/307944. S2CID 11704765.
  11. ^ a b 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.
  12. ^ a b Niemczura, E. (June 2003). "Metallicities of the SPB stars from the IUE ultraviolet spectra". Astronomy and Astrophysics. 404 (2): 689–700. Bibcode:2003A&A...404..689N. doi:10.1051/0004-6361:20030546.. The fractional abundance relative to the Sun is given by:
    10−0.13 = 0.74, or 74%.
  13. ^ a b Dachs, J.; et al. (March 1981). "Photoelectric scanner measurements of Balmer emission line profiles for southern Be stars. II - A survey for variations". Astronomy and Astrophysics Supplement Series. 43: 427–453. Bibcode:1981A&AS...43..427D.
  14. ^ a b Su, K. Y. L.; et al. (December 2006). "Debris Disk Evolution around A Stars". The Astrophysical Journal. 653 (1): 675–689. arXiv:astro-ph/0608563. Bibcode:2006ApJ...653..675S. doi:10.1086/508649. S2CID 14116473.
  15. ^ "LTT 8869 -- High proper-motion Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2011-12-24.
  16. ^ Scalzi, John (2008). Rough Guide to the Universe. Penguin. p. 306. ISBN 978-1-4053-8370-7.
  17. ^ Bowditch, LL.D., Nathaniel (2002) [1802]. "15: Navigational Astronomy" (PDF). The American Practical Navigator: An Epitome of Navigation. Bethesda, MD: National Imagery and Mapping Agency. p. 248. ISBN 978-0-939837-54-0. Retrieved 2016-09-20.
  18. ^ Kunitzsch, P.; Smart, T. (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd ed.). Cambridge, MA: Sky Publishing. p. 39. ISBN 978-1-931559-44-7.
  19. ^ Kunitzsch, P. (1959). Arabische Sternnamen in Europa. Wiesbaden: Otto Harrassowitz. p. 128.
  20. ^ "IAU Working Group on Star Names (WGSN)". International Astronomical Union. Retrieved 22 May 2016.
  21. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
  22. ^ Allen, Richard H. (1963). Star Names: Their Lore and Meaning (reprint ed.). New York, NY: Dover Publications Inc. p. 237. ISBN 978-0-486-21079-7.
  23. ^ 陳久金 (2005). 中國星座神話 (in Chinese). 五南圖書出版股份有限公司. ISBN 978-986-7332-25-7.
  24. ^ (in Chinese). Hong Kong Space Museum. Archived from the original on 2008-10-25. Retrieved 2019-01-15.
  25. ^ Richard Hinckley Allen. "Star Names — Their Lore and Meaning: Grus". Retrieved 2019-01-15.
  26. ^ a b Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  27. ^ Lang, Kenneth R. (2006). Astrophysical formulae. Astronomy and astrophysics library. Vol. 1 (3rd ed.). Birkhäuser. ISBN 978-3-540-29692-8.. The radius (R*) is given by:
     
  28. ^ . Australia Telescope, Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original on March 18, 2012. Retrieved 2012-01-16.
  29. ^ a b Zuckerman, B.; et al. (May 2011). "The Tucana/Horologium, Columba, AB Doradus, and Argus Associations: New Members and Dusty Debris Disks". The Astrophysical Journal. 732 (2): 61. arXiv:1104.0284. Bibcode:2011ApJ...732...61Z. doi:10.1088/0004-637X/732/2/61. S2CID 62797470.

External links

  • Kaler, James B., "AL NAIR (Alpha Gruis)", Stars, University of Illinois, retrieved 2011-12-26

May 21, 2023
alpha, gruis, alnair, redirects, here, star, centaurus, zeta, centauri, brightest, star, southern, constellation, grus, officially, named, alnair, star, bayer, designation, which, latinized, from, gruis, abbreviated, with, magnitude, brightest, stars, fifty, e. Alnair redirects here For the star in Centaurus see Zeta Centauri Alpha Gruis is the brightest star in the southern constellation of Grus It is officially named Alnair 1 Alpha Gruis is the star s Bayer designation which is Latinized from a Gruis and abbreviated a Gru With an magnitude of 1 7 it is one of the brightest stars in the sky and one of the fifty eight stars selected for celestial navigation Alpha Gruis is a single B type main sequence star located at a distance of 31 pc Alpha GruisLocation of a Gruis circled Observation dataEpoch J2000 Equinox J2000Constellation GrusPronunciation ae l ˈ n ɛer 1 Right ascension 22h 08m 13 98473s 2 Declination 46 57 39 5078 2 Apparent magnitude V 1 74 3 CharacteristicsSpectral type B6 V 4 U B color index 0 47 3 B V color index 0 13 3 AstrometryRadial velocity Rv 11 8 5 km sProper motion m RA 126 69 2 mas yr Dec 147 47 2 mas yrParallax p 32 29 0 21 mas 2 Distance101 0 0 7 ly 31 0 0 2 pc Absolute magnitude MV 0 72 6 DetailsMass4 0 7 M Radius3 4 8 R Luminosity520 9 L Surface gravity log g 3 76 0 11 10 cgsTemperature13 920 11 KMetallicity Fe H 0 13 0 02 12 dexRotational velocity v sin i 215 13 km sAge100 14 MyrOther designationsAl Na ir a Gru CD 47 14063 FK5 829 GJ 848 2 HD 209952 HIP 109268 HR 8425 SAO 230992 15 Database referencesSIMBADdata Contents 1 Nomenclature 2 Properties 3 References 4 External linksNomenclature Edita Gruis Latinised to Alpha Gruis is the star s Bayer designation Its first depiction in a celestial atlas was in Johann Bayer s Uranometria of 1603 16 It bore the traditional name Alnair or Al Nair sometimes Al Na ir in lists of stars used by navigators 17 from the Arabic al nayyir the bright one itself derived from its Arabic name al nayyir min dhanab al ḥut al janubiyy the bright one from the southern fish s tail see Aldhanab 18 Confusingly Alnair was also given as the proper name for Zeta Centauri in an astronomical ephemerides in the middle of the 20th century 19 In 2016 the International Astronomical Union organized a Working Group on Star Names WGSN 20 to catalog and standardize proper names for stars The WGSN approved the name Alnair for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names 21 Along with Beta Gruis Delta Gruis Theta Gruis Iota Gruis and Lambda Gruis Alpha Gruis belonged to Piscis Austrinus in traditional Arabic astronomy 22 In Chinese 鶴 He meaning Crane refers to an asterism consisting of Alpha Gruis Beta Gruis Delta2 Gruis Epsilon Gruis Zeta Gruis Eta Gruis Iota Gruis Theta Gruis Mu1 Gruis and Delta Tucanae 23 Consequently Alpha Gruis itself is known as 鶴一 He yi English First Star of the Crane 24 The Chinese name gave rise to another English name Ke 25 Properties EditAlpha Gruis has a stellar classification of B6 V 4 although some sources give it a classification of B7 IV 26 The first classification indicates that this is a B type star on the main sequence of stars that are generating energy through the thermonuclear fusion of hydrogen at the core However a luminosity class of IV would suggest that this is a subgiant star meaning the supply of hydrogen at its core is becoming exhausted and the star has started the process of evolving away from the main sequence It has no known companions 26 The measured angular diameter of this star after correcting for limb darkening is 1 02 0 07 mas 8 At a parallax measured distance of 101 light years 31 parsecs from Earth this yields a physical size of 3 4 times the radius of the Sun 27 It is rotating rapidly with a projected rotational velocity of about 215 km s providing a lower bound for the rate of azimuthal rotation along the equator 13 This star has around four times the Sun s mass and is radiating roughly 520 times the luminosity of the Sun 9 The effective temperature of Alpha Gruis s outer envelope is 13 920 K 11 giving it the blue white hue characteristic of B type stars 28 The abundance of elements other than hydrogen and helium what astronomers term the metallicity is about 74 of the abundance in the Sun 12 Based on the estimated age and motion it may be a member of the AB Doradus moving group that share a common motion through space This group has an age of about 70 million years 29 which is consistent with a Gruis s 100 million year 14 estimated age allowing for a margin of error The space velocity components of this star in the Galactic coordinate system are U V W 7 0 1 1 25 6 0 7 15 5 1 4 km s 29 References Edit a b Kunitzsch Paul Smart Tim 2006 A Dictionary of Modern star Names A Short Guide to 254 Star Names and Their Derivations 2nd rev ed Cambridge Massachusetts Sky Pub ISBN 978 1 931559 44 7 a b c d e van Leeuwen F November 2007 Validation of the new Hipparcos reduction Astronomy and Astrophysics 474 2 653 664 arXiv 0708 1752 Bibcode 2007A amp A 474 653V doi 10 1051 0004 6361 20078357 S2CID 18759600 a b c Hoffleit D Warren W H Jr HR 8425 database entry The Bright Star Catalogue 5th Revised Preliminary ed CDS Retrieved 5 September 2015 a b Gray R O et al July 2006 Contributions to the Nearby Stars NStars Project spectroscopy of stars earlier than M0 within 40 pc The Southern Sample The Astronomical Journal 132 1 161 170 arXiv astro ph 0603770 Bibcode 2006AJ 132 161G doi 10 1086 504637 S2CID 119476992 Wilson Ralph Elmer 1953 General catalogue of stellar radial velocities Washington 0 Bibcode 1953GCRV C 0W 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 Malagnini M L Morossi C November 1990 Accurate absolute luminosities effective temperatures radii masses and surface gravities for a selected sample of field stars Astronomy and Astrophysics Supplement Series 85 3 1015 1019 Bibcode 1990A amp AS 85 1015M a b Richichi A Percheron I Khristoforova M February 2005 CHARM2 An updated Catalog of High Angular Resolution Measurements Astronomy and Astrophysics 431 2 773 777 Bibcode 2005A amp A 431 773R doi 10 1051 0004 6361 20042039 a b McCarthy K White R J June 2012 The Sizes of the Nearest Young Stars The Astronomical Journal 143 6 134 arXiv 1201 6600 Bibcode 2012AJ 143 134M doi 10 1088 0004 6256 143 6 134 S2CID 118538522 Fitzpatrick Edward L Massa Derck November 1999 Determining the Physical Properties of the B Stars I Methodology and First Results The Astrophysical Journal 525 2 1011 1023 arXiv astro ph 9906257 Bibcode 1999ApJ 525 1011F doi 10 1086 307944 S2CID 11704765 a b 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 a b Niemczura E June 2003 Metallicities of the SPB stars from the IUE ultraviolet spectra Astronomy and Astrophysics 404 2 689 700 Bibcode 2003A amp A 404 689N doi 10 1051 0004 6361 20030546 The fractional abundance relative to the Sun is given by 10 0 13 0 74 or 74 a b Dachs J et al March 1981 Photoelectric scanner measurements of Balmer emission line profiles for southern Be stars II A survey for variations Astronomy and Astrophysics Supplement Series 43 427 453 Bibcode 1981A amp AS 43 427D a b Su K Y L et al December 2006 Debris Disk Evolution around A Stars The Astrophysical Journal 653 1 675 689 arXiv astro ph 0608563 Bibcode 2006ApJ 653 675S doi 10 1086 508649 S2CID 14116473 LTT 8869 High proper motion Star SIMBAD Centre de Donnees astronomiques de Strasbourg Retrieved 2011 12 24 Scalzi John 2008 Rough Guide to the Universe Penguin p 306 ISBN 978 1 4053 8370 7 Bowditch LL D Nathaniel 2002 1802 15 Navigational Astronomy PDF The American Practical Navigator An Epitome of Navigation Bethesda MD National Imagery and Mapping Agency p 248 ISBN 978 0 939837 54 0 Retrieved 2016 09 20 Kunitzsch P Smart T 2006 A Dictionary of Modern star Names A Short Guide to 254 Star Names and Their Derivations 2nd ed Cambridge MA Sky Publishing p 39 ISBN 978 1 931559 44 7 Kunitzsch P 1959 Arabische Sternnamen in Europa Wiesbaden Otto Harrassowitz p 128 IAU Working Group on Star Names WGSN International Astronomical Union Retrieved 22 May 2016 IAU Catalog of Star Names Retrieved 28 July 2016 Allen Richard H 1963 Star Names Their Lore and Meaning reprint ed New York NY Dover Publications Inc p 237 ISBN 978 0 486 21079 7 陳久金 2005 中國星座神話 in Chinese 五南圖書出版股份有限公司 ISBN 978 986 7332 25 7 香港太空館 研究資源 亮星中英對照表 in Chinese Hong Kong Space Museum Archived from the original on 2008 10 25 Retrieved 2019 01 15 Richard Hinckley Allen Star Names Their Lore and Meaning Grus Retrieved 2019 01 15 a b Eggleton P P Tokovinin A A September 2008 A catalogue of multiplicity among bright stellar systems Monthly Notices of the Royal Astronomical Society 389 2 869 879 arXiv 0806 2878 Bibcode 2008MNRAS 389 869E doi 10 1111 j 1365 2966 2008 13596 x S2CID 14878976 Lang Kenneth R 2006 Astrophysical formulae Astronomy and astrophysics library Vol 1 3rd ed Birkhauser ISBN 978 3 540 29692 8 The radius R is given by 2 R 10 3 31 1 02 AU 0 0046491 AU R 6 8 R displaystyle begin aligned 2 cdot R amp frac 10 3 cdot 31 cdot 1 02 text AU 0 0046491 text AU R bigodot amp approx 6 8 cdot R bigodot end aligned The Colour of Stars Australia Telescope Outreach and Education Commonwealth Scientific and Industrial Research Organisation December 21 2004 Archived from the original on March 18 2012 Retrieved 2012 01 16 a b Zuckerman B et al May 2011 The Tucana Horologium Columba AB Doradus and Argus Associations New Members and Dusty Debris Disks The Astrophysical Journal 732 2 61 arXiv 1104 0284 Bibcode 2011ApJ 732 61Z doi 10 1088 0004 637X 732 2 61 S2CID 62797470 External links EditKaler James B AL NAIR Alpha Gruis Stars University of Illinois retrieved 2011 12 26 Retrieved from https en wikipedia org w index php title Alpha Gruis amp oldid 1094156223, wikipedia, wiki, book, books, library,

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