The primary star, ε Sagittarii A, of this binary star system has a stellar classification of B9.5 III,[3] with the luminosity class of III suggesting this is an evolvedgiant star that has exhausted the supply of hydrogen at its core. The interferometry-measured angular diameter of this star, after correcting for limb darkening, is 1.44 ± 0.06 mas,[12] which, at its estimated distance, equates to a physical radius of about 6.8 times the radius of the Sun.[6] This is a close match to the empirically-determined value of 6.9 solar radii.[13] It has about 3.5 times the mass of the Sun and is radiating around 363 times the Sun's luminosity from its outer atmosphere at an effective temperature of 9,960 K.[5] At this heat, the star glows with a blue-white hue.[14]
This star is spinning rapidly with a projected rotational velocity of 236 km s−1.[9] It has a magnetic field with a strength in the range 10.5–130.5 Gauss[15] and it is an X-ray source with a luminosity of about 1030 erg s−1.[5] The system displays an excess emission of infrared radiation, which suggests the presence of a circumstellar disk of dust. Based upon the temperature of this disk, it is orbiting at a mean separation of 155 AU from the primary.[16]
As of 2001, the secondary star, ε Sagittarii B, is located at an angular separation of 2.392 arcseconds from the primary along a position angle of 142.3°. At the distance of this system, this angle is equivalent to a physical separation of about 106 AU, which places it inside the debris disk. It is a main sequence star with about 95% of the mass of the Sun. The system has a higher optical linear polarisation than expected for its distance from the Sun; this has been attributed to light scattered off the disk from the secondary.[17] Prior to its 1993 identification using an adaptive opticscoronagraph, this companion may have been responsible for the spectral anomalies that were attributed to the primary star.[18] There is a candidate stellar companion at an angular separation of 32.3 arcseconds.[5]
It bore the traditional name Kaus Australis, which derived from the Arabic قوس qaws 'bow' and Latinaustrālis 'southern'. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[19] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[20] included a table of the first two batches of names approved by the WGSN; which included Kaus Australis for the star ε Sagittarii A.
In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Thalath al Waridah, or Thalith al Waridah, meaning 'third of Warida'.[21]
^ abcdevan 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
^ abcdJohnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4: 99–100, Bibcode:1966CoLPL...4...99J
^ abHouk, Nancy; Smith-Moore, M. (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 -40.0° to -26.0°, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, 3, Bibcode:1982mcts.book.....H
^Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. Determination of Radial Velocities and Their Applications. Vol. 30. University of Toronto: International Astronomical Union. p. 57. Bibcode:1967IAUS...30...57E.
^ abcdefghijHubrig, S.; Le Mignant, D.; North, P.; Krautter, J. (June 2001), "Search for low-mass PMS companions around X-ray selected late B stars", Astronomy and Astrophysics, 372: 152–164, arXiv:astro-ph/0103201, Bibcode:2001A&A...372..152H, doi:10.1051/0004-6361:20010452, S2CID 17507782
^ abLang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN3-540-29692-1. The radius (R*) is given by:
^Adelman, Saul J. (December 2004). "The physical properties of normal A stars". In Zverko, J.; Ziznovsky, J.; Adelman, S. J.; Weiss, W. W. (eds.). The A-Star Puzzle, held in Poprad, Slovakia, July 8-13, 2004. IAU Symposium. Vol. 2004, no. 224. Cambridge, UK: Cambridge University Press. pp. 1–11. Bibcode:2004IAUS..224....1A. doi:10.1017/S1743921304004314.
^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
^ abRoyer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393 (3): 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943, S2CID 14070763
^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. ISBN978-1-931559-44-7.
^"IAU Catalog of Star Names". Retrieved 28 July 2016.
^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
^Jerzykiewicz, M.; Molenda-Zakowicz, J. (September 2000), "Empirical Luminosities and Radii of Early-Type Stars after Hipparcos", Acta Astronomica, 50: 369–380, Bibcode:2000AcA....50..369J
^Bychkov, V. D.; Bychkova, L. V.; Madej, J. (August 2003), "Catalogue of averaged stellar effective magnetic fields. I. Chemically peculiar A and B type stars", Astronomy and Astrophysics, 407 (2): 631–642, arXiv:astro-ph/0307356, Bibcode:2003A&A...407..631B, doi:10.1051/0004-6361:20030741, S2CID 14184105
^Rodriguez, David R.; Zuckerman, B. (February 2012), "Binaries among Debris Disk Stars", The Astrophysical Journal, 745 (2): 147, arXiv:1111.5618, Bibcode:2012ApJ...745..147R, doi:10.1088/0004-637X/745/2/147, S2CID 73681879
^Cotton, D. V.; et al. (January 2016). "The linear polarization of Southern bright stars measured at the parts-per-million level". Monthly Notices of the Royal Astronomical Society. 455 (2): 1607–1628. arXiv:1509.07221. Bibcode:2016MNRAS.455.1607C. doi:10.1093/mnras/stv2185. S2CID 11191040.
^Golimowski, David A.; Durrance, Samuel T.; Clampin, Mark (March 1993), "Detection of an apparent star 2.1 arcsec from the circumstellar disk candidate Epsilon Sagittarii", Astronomical Journal, 105 (3): 1108–1113, Bibcode:1993AJ....105.1108G, doi:10.1086/116498
^"IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
^"Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
^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): 435. 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
^ abAllen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc. p. 355. ISBN0-486-21079-0. Retrieved 2012-09-04.
^Rogers, J. H. (February 1998), "Origins of the ancient constellations: I. The Mesopotamian traditions", Journal of the British Astronomical Association, 108 (1): 9–28, Bibcode:1998JBAA..108....9R
^Basso, Ellen B. (1987). In Favor of Deceit: A Study of Tricksters in an Amazonian Society. Tucson, Arizona: University of Arizona Press. p. 360. ISBN0-8165-1022-9.
External links
May 19, 2023
epsilon, sagittarii, latinised, from, sagittarii, abbreviated, epsilon, formally, named, kaus, australis, ɔː, ɔː, binary, star, system, southern, zodiac, constellation, sagittarius, apparent, visual, magnitude, makes, brightest, object, sagittarius, based, upo. Epsilon Sagittarii Latinised from e Sagittarii abbreviated Epsilon Sgr e Sgr formally named Kaus Australis ˈ k ɔː s ɔː ˈ s t r eɪ l ɪ s 10 11 is a binary star system in the southern zodiac constellation of Sagittarius The apparent visual magnitude of 1 85 2 makes it the brightest object in Sagittarius Based upon parallax measurements this star is around 143 light years 44 parsecs from the Sun e SagittariiLocation of e Sagittarii circled Observation dataEpoch J2000 Equinox J2000Constellation SagittariusRight ascension 18h 24m 10 31840s 1 Declination 34 23 04 6193 1 Apparent magnitude V 1 85 2 CharacteristicsSpectral type B9 5 III 3 U B color index 0 13 2 B V color index 0 03 2 AstrometryRadial velocity Rv 15 4 km sProper motion m RA 39 42 1 mas yr Dec 124 20 1 mas yrParallax p 22 76 0 24 mas 1 Distance143 2 ly 43 9 0 5 pc Absolute magnitude MV 1 41 5 Detailse Sgr AMass3 515 0 138 5 M Radius6 8 6 R Luminosity363 5 L Surface gravity log g 4 50 7 cgsTemperature9 960 8 KRotational velocity v sin i 236 9 km sAge232 5 Myre Sgr BMass0 95 5 M Luminosity0 89 5 L Temperature5 807 5 KOther designationsKaus Australis e Sagittarii e Sgr Epsilon Sgr 20 Sagittarii CCDM J18242 3423A FK5 689 GC 25100 HD 169022 HIP 90185 HR 6879 IDS 18175 3427 A PPM 297655 SAO 210091 WDS J18242 3423ADatabase referencesSIMBADdata Contents 1 Stellar system 2 Nomenclature 3 References 4 External linksStellar system EditThe primary star e Sagittarii A of this binary star system has a stellar classification of B9 5 III 3 with the luminosity class of III suggesting this is an evolved giant star that has exhausted the supply of hydrogen at its core The interferometry measured angular diameter of this star after correcting for limb darkening is 1 44 0 06 mas 12 which at its estimated distance equates to a physical radius of about 6 8 times the radius of the Sun 6 This is a close match to the empirically determined value of 6 9 solar radii 13 It has about 3 5 times the mass of the Sun and is radiating around 363 times the Sun s luminosity from its outer atmosphere at an effective temperature of 9 960 K 5 At this heat the star glows with a blue white hue 14 This star is spinning rapidly with a projected rotational velocity of 236 km s 1 9 It has a magnetic field with a strength in the range 10 5 130 5 Gauss 15 and it is an X ray source with a luminosity of about 1030 erg s 1 5 The system displays an excess emission of infrared radiation which suggests the presence of a circumstellar disk of dust Based upon the temperature of this disk it is orbiting at a mean separation of 155 AU from the primary 16 As of 2001 the secondary star e Sagittarii B is located at an angular separation of 2 392 arcseconds from the primary along a position angle of 142 3 At the distance of this system this angle is equivalent to a physical separation of about 106 AU which places it inside the debris disk It is a main sequence star with about 95 of the mass of the Sun The system has a higher optical linear polarisation than expected for its distance from the Sun this has been attributed to light scattered off the disk from the secondary 17 Prior to its 1993 identification using an adaptive optics coronagraph this companion may have been responsible for the spectral anomalies that were attributed to the primary star 18 There is a candidate stellar companion at an angular separation of 32 3 arcseconds 5 Nomenclature Edite Sagittarii Latinised to Epsilon Sagittarii is the star system s Bayer designation It bore the traditional name Kaus Australis which derived from the Arabic قوس qaws bow and Latin australis southern In 2016 the International Astronomical Union organized a Working Group on Star Names WGSN 19 to catalog and standardize proper names for stars The WGSN s first bulletin of July 2016 20 included a table of the first two batches of names approved by the WGSN which included Kaus Australis for the star e Sagittarii A In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket this star was designated Thalath al Waridah or Thalith al Waridah meaning third of Warida 21 In Chinese 箕 Ji meaning Winnowing Basket refers to an asterism consisting of Epsilon Sagittarii Gamma Sagittarii Delta Sagittarii and Eta Sagittarii Consequently the Chinese name for Epsilon Sagittarii itself is 箕宿三 Ji Su san English the Third Star of Winnowing Basket 22 This star together with Gamma Sagittarii Delta Sagittarii Zeta Sagittarii Lambda Sagittarii Sigma Sagittarii Tau Sagittarii and Phi Sagittarii comprise the Teapot asterism 23 Gamma Sagittarii Delta Sagittarii and Eta Sagittarii were Al Naʽam al Warid النعم الوارد the Going Ostriches 24 Gamma Sagittarii and Delta Sagittarii were Akkadian Sin nun tu or Si nu nu tum the Swallow 24 Kaus Australis is listed in the Babylonian compendium MUL APIN as MA GUR8 meaning the Bark 25 The Kalapalo people of Mato Grosso state in Brazil called this star and l Scorpii through i Scorpii 8 Scorpii n Scorpii y Scorpii and r Scorpii Taugi kusugu Taugi s fishing basket 26 References Edit 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 d Johnson H L et al 1966 UBVRIJKL photometry of the bright stars Communications of the Lunar and Planetary Laboratory 4 99 100 Bibcode 1966CoLPL 4 99J a b Houk Nancy Smith Moore M 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 0 to 26 0 Ann Arbor Michigan Dept of Astronomy University of Michigan 3 Bibcode 1982mcts book H Evans D S June 20 24 1966 The Revision of the General Catalogue of Radial Velocities In Batten Alan Henry Heard John Frederick eds Determination of Radial Velocities and their Applications Proceedings from IAU Symposium no 30 Determination of Radial Velocities and Their Applications Vol 30 University of Toronto International Astronomical Union p 57 Bibcode 1967IAUS 30 57E a b c d e f g h i j Hubrig S Le Mignant D North P Krautter J June 2001 Search for low mass PMS companions around X ray selected late B stars Astronomy and Astrophysics 372 152 164 arXiv astro ph 0103201 Bibcode 2001A amp A 372 152H doi 10 1051 0004 6361 20010452 S2CID 17507782 a b Lang Kenneth R 2006 Astrophysical formulae Astronomy and astrophysics library vol 1 3rd ed Birkhauser ISBN 3 540 29692 1 The radius R is given by 2 R 10 3 43 9 1 44 AU 0 0046491 AU R 13 6 R displaystyle begin aligned 2 cdot R amp frac 10 3 cdot 43 9 cdot 1 44 text AU 0 0046491 text AU R bigodot amp approx 13 6 cdot R bigodot end aligned Adelman Saul J December 2004 The physical properties of normal A stars In Zverko J Ziznovsky J Adelman S J Weiss W W eds The A Star Puzzle held in Poprad Slovakia July 8 13 2004 IAU Symposium Vol 2004 no 224 Cambridge UK Cambridge University Press pp 1 11 Bibcode 2004IAUS 224 1A doi 10 1017 S1743921304004314 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 Royer F et al October 2002 Rotational velocities of A type stars in the northern hemisphere II Measurement of v sin i Astronomy and Astrophysics 393 3 897 911 arXiv astro ph 0205255 Bibcode 2002A amp A 393 897R doi 10 1051 0004 6361 20020943 S2CID 14070763 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 IAU Catalog of Star Names Retrieved 28 July 2016 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 Jerzykiewicz M Molenda Zakowicz J September 2000 Empirical Luminosities and Radii of Early Type Stars after Hipparcos Acta Astronomica 50 369 380 Bibcode 2000AcA 50 369J The Colour of Stars Australia Telescope Outreach and Education Commonwealth Scientific and Industrial Research Organisation December 21 2004 archived from the original on 2012 03 18 retrieved 2012 01 16 Bychkov V D Bychkova L V Madej J August 2003 Catalogue of averaged stellar effective magnetic fields I Chemically peculiar A and B type stars Astronomy and Astrophysics 407 2 631 642 arXiv astro ph 0307356 Bibcode 2003A amp A 407 631B doi 10 1051 0004 6361 20030741 S2CID 14184105 Rodriguez David R Zuckerman B February 2012 Binaries among Debris Disk Stars The Astrophysical Journal 745 2 147 arXiv 1111 5618 Bibcode 2012ApJ 745 147R doi 10 1088 0004 637X 745 2 147 S2CID 73681879 Cotton D V et al January 2016 The linear polarization of Southern bright stars measured at the parts per million level Monthly Notices of the Royal Astronomical Society 455 2 1607 1628 arXiv 1509 07221 Bibcode 2016MNRAS 455 1607C doi 10 1093 mnras stv2185 S2CID 11191040 Golimowski David A Durrance Samuel T Clampin Mark March 1993 Detection of an apparent star 2 1 arcsec from the circumstellar disk candidate Epsilon Sagittarii Astronomical Journal 105 3 1108 1113 Bibcode 1993AJ 105 1108G doi 10 1086 116498 IAU Working Group on Star Names WGSN Retrieved 22 May 2016 Bulletin of the IAU Working Group on Star Names No 1 PDF Retrieved 28 July 2016 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 8 435 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 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 Rogers J H February 1998 Origins of the ancient constellations I The Mesopotamian traditions Journal of the British Astronomical Association 108 1 9 28 Bibcode 1998JBAA 108 9R Basso Ellen B 1987 In Favor of Deceit A Study of Tricksters in an Amazonian Society Tucson Arizona University of Arizona Press p 360 ISBN 0 8165 1022 9 External links EditKaus Australis Retrieved from https en wikipedia org w index php title Epsilon Sagittarii amp oldid 1141386023, wikipedia, wiki, book, books, library,
