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Sextans

January 01, 1970

This article is about the constellation. For the ancient Roman coin, see sextans (coin). For the Sextans dwarf galaxy, see Sextans Dwarf Spheroidal.

Sextans is a faint, minor constellation on the celestial equator which was introduced in 1687 by Polish astronomer Johannes Hevelius. Its name is Latin for the astronomical sextant, an instrument that Hevelius made frequent use of in his observations.

Sextans
Constellation
AbbreviationSex
GenitiveSextantis, Sextansis
Pronunciation/ˈsɛkstənz/,
genitive /sɛksˈtæntɪs/
Symbolismthe Sextant
Right ascension09h 41m 04.8653s–10h 51m 30.2447s[1]
Declination6.4327669°–−11.6621428°[1]
QuadrantSQ2
Area314 sq. deg. (47th)
Main stars3
Bayer/Flamsteed
stars		28
Stars with planets5
Stars brighter than 3.00m0
Stars within 10.00 pc (32.62 ly)5
Brightest starα Sex (4.49m)
Messier objects0
Meteor showersSextantids
Bordering
constellations		Leo
Hydra
Crater
Visible at latitudes between +80° and −90°.
Best visible at 21:00 (9 p.m.) during the month of April.

Notable features edit

Sextans as a constellation covers a rather dim, sparse region of the sky. It has only one star above the fifth magnitude, namely α Sextantis at 4.49m. Altogether, there are 38 stars that are brighter than or equal to apparent magnitude 6.5.[a][3] John Flamsteed labeled 41 stars for the constellation.[4] Francis Baily intended to give Bayer designations to some of the stars but because none of them were above magnitude 4.5, he left them unlettered.[4] Rather, it was Benjamin Apthorp Gould who lettered some of the stars. He labeled the five brightest stars using Greek letters Alpha (α) to Epsilon (ε) in his Uranometria Argentina.[4]

Because it is close to the ecliptic plane, the Moon and planets regularly cross the constellation, especially its northeastern corner.

Stars edit

See also: List of stars in Sextans
 
The constellation Sextans as it can be seen by the naked eye


Bright Stars edit

Multiple Star Systems edit

  • 35 Sextantis is a triples star system consisting of two evolved K-type giants of equal mass, with both stars being twice as massive as the Sun.[14] The secondary is itself a single-lined spectroscopic binary consisting of a 0.58 M☉ companion and itself.[14] The system is located approximately 700 light years away.[15][16] The outer pair has a separation of 6.8" and both stars take roughly 23,000 years to orbit each other while the B subsystem takes 1,528 days to circle each other in a relatively eccentric orbit.[17]


There are a few notable variable stars, including 25, 23 Sextantis, and LHS 292. NGC 3115, an edge-on lenticular galaxy, is the only noteworthy deep-sky object. It also lies near the ecliptic, which causes the Moon, and some of the planets to occasionally pass through it for brief periods of time.

The constellation is the location of the field studied by the COSMOS project, undertaken by the Hubble Space Telescope.

COSMOS project edit

  •  
    COSMOS-Gr30 is a particularly dense region in space that contains 10 individual galaxies[18]
  •  
    Cosmos Redshift 7, brightest galaxy in the early universe, is located in the constellation Sextans (artist concept)

Sextans B is a fairly bright dwarf irregular galaxy at magnitude 6.6, 4.3 million light-years from Earth. It is part of the Local Group of galaxies.[19]

CL J1001+0220 is as of 2016 the most distant-known galaxy cluster at redshift z=2.506, 11.1 billion light-years from Earth.[20]

In June 2015, astronomers reported evidence for population III stars in the Cosmos Redshift 7 galaxy (at z = 6.60) found in Sextans. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.[21][22]

Depictions of the constellation edit

  •  
    The constellation Sextans as depicted in Johann Doppelmayr's Atlas Coelestis, c. 1730 (Plate 19, Southern Celestial Hemisphere).
  •  
    Sextans and other constellations seen around Hydra. From Urania's Mirror (1825)

See also edit

References edit

  1. ^ a b IAU, The Constellations, Sextans.
  2. ^ Bortle, John E. (February 2001). "The Bortle Dark-Sky Scale". Sky & Telescope. Sky Publishing Corporation. Retrieved 4 March 2016.
  3. ^ Ridpath, Ian. "Constellations: Lacerta–Vulpecula". Star Tales. Self-published. Retrieved 4 March 2016.
  4. ^ a b c Wagman, Morton (2003). Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others. Blacksburg, VA: The McDonald & Woodward Publishing Company. p. 290. ISBN 978-0-939923-78-6.
  5. ^ Cowley, A.; Cowley, C.; Jaschek, M.; Jaschek, C. (April 1969). "A study of the bright stars. I. A catalogue of spectral classifications". The Astronomical Journal. 74: 375. Bibcode:1969AJ.....74..375C. doi:10.1086/110819. ISSN 0004-6256. S2CID 121555804.
  6. ^ a b van Leeuwen, F. (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.
  7. ^ Monier, Richard; Bowman, Dominic M.; Lebreton, Yveline; Deal, Morgan (2023). "The Unexpected Optical and Ultraviolet Variability of the Standard Star α Sex (HD 87887)". The Astronomical Journal. 166 (2): 73. arXiv:2306.08551. Bibcode:2023AJ....166...73M. doi:10.3847/1538-3881/acdee4.
  8. ^ Edwards, T. W. (April 1976), "MK classification for visual binary components", Astronomical Journal, 81: 245–249, Bibcode:1976AJ.....81..245E, doi:10.1086/111879.
  9. ^ a b Heintz, W. D. (March 1982), "Orbits of 16 visual binaries", Astronomy and Astrophysics Supplement Series, 47: 569–573, Bibcode:1982A&AS...47..569H.
  10. ^ Crawford, D. L.; et al. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal, 76: 1058, Bibcode:1971AJ.....76.1058C, doi:10.1086/111220.
  11. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "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. Gaia DR2 record for this source at VizieR.
  12. ^ Mathys, G.; et al. (March 1986), "Photometric variability of some early-type stars", Astronomy and Astrophysics Supplement Series, 63 (3): 403–416, Bibcode:1986A&AS...63..403M.
  13. ^ Kholopov, P. N.; et al. (April 1989), "The 69th Name-List of Variable Stars", Information Bulletin on Variable Stars, 3323 (3323): 1, Bibcode:1989IBVS.3323....1K.
  14. ^ a b Tokovinin, A. (September 11, 2008). "Comparative statistics and origin of triple and quadruple stars". Monthly Notices of the Royal Astronomical Society. 389 (2): 925–938. arXiv:0806.3263. Bibcode:2008MNRAS.389..925T. doi:10.1111/j.1365-2966.2008.13613.x.
  15. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  16. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  17. ^ Tokovinin, A. A.; Gorynya, N. A. (April 2007). "New spectroscopic components in multiple systems. V." Astronomy & Astrophysics. 465 (1): 257–261. Bibcode:2007A&A...465..257T. doi:10.1051/0004-6361:20066888. ISSN 0004-6361. S2CID 34100030.
  18. ^ "A gigantic cosmic bubble". www.eso.org. Retrieved 13 November 2017.
  19. ^ Levy 2005, p. 178.
  20. ^ Wang, Tao; Elbaz, David; Daddi, Emanuele; Finoguenov, Alexis; Liu, Daizhong; Schrieber, Corenin; Martin, Sergio; Strazzullo, Veronica; Valentino, Francesco; van Der Burg, Remco; Zanella, Anita; Cisela, Laure; Gobat, Raphael; Le Brun, Amandine; Pannella, Maurilio; Sargent, Mark; Shu, Xinwen; Tan, Qinghua; Cappelluti, Nico; Li, Xanxia (2016). "Discovery of a galaxy cluster with a violently starbursting core at z=2.506". The Astrophysical Journal. 828 (1): 56. arXiv:1604.07404. Bibcode:2016ApJ...828...56W. doi:10.3847/0004-637X/828/1/56. S2CID 8771287.
  21. ^ Sobral, David; Matthee, Jorryt; Darvish, Behnam; Schaerer, Daniel; Mobasher, Bahram; Röttgering, Huub J. A.; Santos, Sérgio; Hemmati, Shoubaneh (4 June 2015). "Evidence For POPIII-Like Stellar Populations In The Most Luminous LYMAN-α Emitters At The Epoch Of Re-Ionisation: Spectroscopic Confirmation". The Astrophysical Journal. 808 (2): 139. arXiv:1504.01734. Bibcode:2015ApJ...808..139S. doi:10.1088/0004-637x/808/2/139. S2CID 18471887.
  22. ^ Overbye, Dennis (17 June 2015). "Astronomers Report Finding Earliest Stars That Enriched Cosmos". New York Times. Retrieved 17 June 2015.

Notes edit

  1. ^ Objects of magnitude 6.5 are among the faintest visible to the unaided eye in suburban–rural transition night skies.[2]

External links edit

 
Wikimedia Commons has media related to Sextans.
  • The Deep Photographic Guide to the Constellations: Sextans
  • Clickable Sextans
  • Star Tales – Sextans


January 01, 1970
sextans, this, article, about, constellation, ancient, roman, coin, sextans, coin, dwarf, galaxy, dwarf, spheroidal, faint, minor, constellation, celestial, equator, which, introduced, 1687, polish, astronomer, johannes, hevelius, name, latin, astronomical, se. This article is about the constellation For the ancient Roman coin see sextans coin For the Sextans dwarf galaxy see Sextans Dwarf Spheroidal Sextans is a faint minor constellation on the celestial equator which was introduced in 1687 by Polish astronomer Johannes Hevelius Its name is Latin for the astronomical sextant an instrument that Hevelius made frequent use of in his observations SextansConstellationList of stars in SextansAbbreviationSexGenitiveSextantis SextansisPronunciation ˈ s ɛ k s t en z genitive s ɛ k s ˈ t ae n t ɪ s Symbolismthe SextantRight ascension09h 41m 04 8653s 10h 51m 30 2447s 1 Declination6 4327669 11 6621428 1 QuadrantSQ2Area314 sq deg 47th Main stars3Bayer Flamsteedstars28Stars with planets5Stars brighter than 3 00m0Stars within 10 00 pc 32 62 ly 5Brightest stara Sex 4 49m Messier objects0Meteor showersSextantidsBorderingconstellationsLeoHydraCraterVisible at latitudes between 80 and 90 Best visible at 21 00 9 p m during the month of April Contents 1 Notable features 2 Stars 2 1 Bright Stars 2 2 Multiple Star Systems 3 COSMOS project 4 Depictions of the constellation 5 See also 6 References 7 Notes 8 External linksNotable features editSextans as a constellation covers a rather dim sparse region of the sky It has only one star above the fifth magnitude namely a Sextantis at 4 49m Altogether there are 38 stars that are brighter than or equal to apparent magnitude 6 5 a 3 John Flamsteed labeled 41 stars for the constellation 4 Francis Baily intended to give Bayer designations to some of the stars but because none of them were above magnitude 4 5 he left them unlettered 4 Rather it was Benjamin Apthorp Gould who lettered some of the stars He labeled the five brightest stars using Greek letters Alpha a to Epsilon e in his Uranometria Argentina 4 Because it is close to the ecliptic plane the Moon and planets regularly cross the constellation especially its northeastern corner Stars editSee also List of stars in Sextans nbsp The constellation Sextans as it can be seen by the naked eye Bright Stars edit Alpha Sextantis is an ageing A type star of spectral class A0 III 5 located 280 20 light years away 6 from the Solar System At the age of 385 million years 7 it is exhausting hydrogen at its core and leaving the main sequence g Sextantis is the second brightest star in the constellation with an apparent magnitude of 5 05 It is a binary star consisting of two A type main sequence stars with classes of A1 V and A4 V respectively 8 The stars take 77 55 years to circle each other in an eccentric orbit 9 and the system is located 280 10 light years away from the Solar System 6 The separation of the stars is four tenths of an arcsecond 9 making it difficult to observe without the use of a telescope with an aperture of 30 cm b Sextantis is slightly fainter at magnitude 5 07 10 it is said to be 364 10 light years distant 11 Beta Sextantis is a B type main sequence star of spectral class B6 V and it has been used as a standard in the MK spectral classification system 12 It is suspected to be a Alpha2 Canum Venaticorum variable with a period of 15 4 days 13 Multiple Star Systems edit 35 Sextantis is a triples star system consisting of two evolved K type giants of equal mass with both stars being twice as massive as the Sun 14 The secondary is itself a single lined spectroscopic binary consisting of a 0 58 M companion and itself 14 The system is located approximately 700 light years away 15 16 The outer pair has a separation of 6 8 and both stars take roughly 23 000 years to orbit each other while the B subsystem takes 1 528 days to circle each other in a relatively eccentric orbit 17 There are a few notable variable stars including 25 23 Sextantis and LHS 292 NGC 3115 an edge on lenticular galaxy is the only noteworthy deep sky object It also lies near the ecliptic which causes the Moon and some of the planets to occasionally pass through it for brief periods of time The constellation is the location of the field studied by the COSMOS project undertaken by the Hubble Space Telescope COSMOS project edit nbsp COSMOS Gr30 is a particularly dense region in space that contains 10 individual galaxies 18 nbsp Cosmos Redshift 7 brightest galaxy in the early universe is located in the constellation Sextans artist concept Sextans B is a fairly bright dwarf irregular galaxy at magnitude 6 6 4 3 million light years from Earth It is part of the Local Group of galaxies 19 CL J1001 0220 is as of 2016 the most distant known galaxy cluster at redshift z 2 506 11 1 billion light years from Earth 20 In June 2015 astronomers reported evidence for population III stars in the Cosmos Redshift 7 galaxy at z 6 60 found in Sextans Such stars are likely to have existed in the very early universe i e at high redshift and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it 21 22 Depictions of the constellation edit nbsp The constellation Sextans as depicted in Johann Doppelmayr s Atlas Coelestis c 1730 Plate 19 Southern Celestial Hemisphere nbsp Sextans and other constellations seen around Hydra From Urania s Mirror 1825 See also editSextans Chinese astronomy References edit a b IAU The Constellations Sextans Bortle John E February 2001 The Bortle Dark Sky Scale Sky amp Telescope Sky Publishing Corporation Retrieved 4 March 2016 Ridpath Ian Constellations Lacerta Vulpecula Star Tales Self published Retrieved 4 March 2016 a b c Wagman Morton 2003 Lost Stars Lost Missing and Troublesome Stars from the Catalogues of Johannes Bayer Nicholas Louis de Lacaille John Flamsteed and Sundry Others Blacksburg VA The McDonald amp Woodward Publishing Company p 290 ISBN 978 0 939923 78 6 Cowley A Cowley C Jaschek M Jaschek C April 1969 A study of the bright stars I A catalogue of spectral classifications The Astronomical Journal 74 375 Bibcode 1969AJ 74 375C doi 10 1086 110819 ISSN 0004 6256 S2CID 121555804 a b van Leeuwen F 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 Monier Richard Bowman Dominic M Lebreton Yveline Deal Morgan 2023 The Unexpected Optical and Ultraviolet Variability of the Standard Star a Sex HD 87887 The Astronomical Journal 166 2 73 arXiv 2306 08551 Bibcode 2023AJ 166 73M doi 10 3847 1538 3881 acdee4 Edwards T W April 1976 MK classification for visual binary components Astronomical Journal 81 245 249 Bibcode 1976AJ 81 245E doi 10 1086 111879 a b Heintz W D March 1982 Orbits of 16 visual binaries Astronomy and Astrophysics Supplement Series 47 569 573 Bibcode 1982A amp AS 47 569H Crawford D L et al 1971 Four color H beta and UBV photometry for bright B type stars in the northern hemisphere The Astronomical Journal 76 1058 Bibcode 1971AJ 76 1058C doi 10 1086 111220 Brown A G A et al Gaia collaboration August 2018 Gaia Data Release 2 Summary of the contents and survey properties Astronomy amp Astrophysics 616 A1 arXiv 1804 09365 Bibcode 2018A amp A 616A 1G doi 10 1051 0004 6361 201833051 Gaia DR2 record for this source at VizieR Mathys G et al March 1986 Photometric variability of some early type stars Astronomy and Astrophysics Supplement Series 63 3 403 416 Bibcode 1986A amp AS 63 403M Kholopov P N et al April 1989 The 69th Name List of Variable Stars Information Bulletin on Variable Stars 3323 3323 1 Bibcode 1989IBVS 3323 1K a b Tokovinin A September 11 2008 Comparative statistics and origin of triple and quadruple stars Monthly Notices of the Royal Astronomical Society 389 2 925 938 arXiv 0806 3263 Bibcode 2008MNRAS 389 925T doi 10 1111 j 1365 2966 2008 13613 x Vallenari A et al Gaia collaboration 2023 Gaia Data Release 3 Summary of the content and survey properties Astronomy and Astrophysics 674 A1 arXiv 2208 00211 Bibcode 2023A amp A 674A 1G doi 10 1051 0004 6361 202243940 S2CID 244398875 Gaia DR3 record for this source at VizieR Vallenari A et al Gaia collaboration 2023 Gaia Data Release 3 Summary of the content and survey properties Astronomy and Astrophysics 674 A1 arXiv 2208 00211 Bibcode 2023A amp A 674A 1G doi 10 1051 0004 6361 202243940 S2CID 244398875 Gaia DR3 record for this source at VizieR Tokovinin A A Gorynya N A April 2007 New spectroscopic components in multiple systems V Astronomy amp Astrophysics 465 1 257 261 Bibcode 2007A amp A 465 257T doi 10 1051 0004 6361 20066888 ISSN 0004 6361 S2CID 34100030 A gigantic cosmic bubble www eso org Retrieved 13 November 2017 Levy 2005 p 178 Wang Tao Elbaz David Daddi Emanuele Finoguenov Alexis Liu Daizhong Schrieber Corenin Martin Sergio Strazzullo Veronica Valentino Francesco van Der Burg Remco Zanella Anita Cisela Laure Gobat Raphael Le Brun Amandine Pannella Maurilio Sargent Mark Shu Xinwen Tan Qinghua Cappelluti Nico Li Xanxia 2016 Discovery of a galaxy cluster with a violently starbursting core at z 2 506 The Astrophysical Journal 828 1 56 arXiv 1604 07404 Bibcode 2016ApJ 828 56W doi 10 3847 0004 637X 828 1 56 S2CID 8771287 Sobral David Matthee Jorryt Darvish Behnam Schaerer Daniel Mobasher Bahram Rottgering Huub J A Santos Sergio Hemmati Shoubaneh 4 June 2015 Evidence For POPIII Like Stellar Populations In The Most Luminous LYMAN a Emitters At The Epoch Of Re Ionisation Spectroscopic Confirmation The Astrophysical Journal 808 2 139 arXiv 1504 01734 Bibcode 2015ApJ 808 139S doi 10 1088 0004 637x 808 2 139 S2CID 18471887 Overbye Dennis 17 June 2015 Astronomers Report Finding Earliest Stars That Enriched Cosmos New York Times Retrieved 17 June 2015 Sextans The Constellations International Astronomical Union Levy David H 2005 Deep Sky Objects Prometheus Books ISBN 1 59102 361 0 Ian Ridpath and Wil Tirion 2007 Stars and Planets Guide Collins London ISBN 978 0 00 725120 9 Princeton University Press Princeton ISBN 978 0 691 13556 4 Notes edit Objects of magnitude 6 5 are among the faintest visible to the unaided eye in suburban rural transition night skies 2 External links edit nbsp Wikimedia Commons has media related to Sextans The Deep Photographic Guide to the Constellations Sextans Clickable Sextans Star Tales Sextans Portals nbsp Astronomy nbsp Stars nbsp Spaceflight nbsp Outer space nbsp Solar System Retrieved from https en wikipedia org w index php title Sextans amp oldid 1215774474, wikipedia, wiki, book, books, library,

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