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Alpha Sagittae

January 01, 1970

Alpha Sagittae, formally named Sham /ˈʃæm/,[11][12] is a single[13] star in the northern constellation of Sagitta. Alpha Sagittae is the Bayer designation, which is latinized from α Sagittae and abbreviated Alpha Sge or α Sge. It is visible to the naked eye as a yellow-hued star with an apparent visual magnitude of +4.38.[2] Despite the name, this is not the brightest star in the constellation – that distinction belongs to Gamma Sagittae. Based upon parallax measurements, Alpha Sagittae is approximately 382 light-years from the Sun. It is moving further away from the Earth with a heliocentric radial velocity of 1.7 km/s.[5]

α Sagittae
Location of α Sagittae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagitta
Right ascension 19h 40m 05.7918540977s[1]
Declination +18° 00′ 50.004597761″[1]
Apparent magnitude (V) +4.38[2]
Characteristics
Evolutionary stage bright giant
Spectral type G1 II[3]
B−V color index 0.777±0.014[4]
Astrometry
Radial velocity (Rv)1.72 ± 0.16[5] km/s
Proper motion (μ) RA: 14.630 ± 0.257[1] mas/yr
Dec.: -20.160 ± 0.276[1] mas/yr
Parallax (π)8.5307 ± 0.1848 mas[1]
Distance382 ± 8 ly
(117 ± 3 pc)
Absolute magnitude (MV)−0.96[6]
Details
Mass4.11[7] M☉
Radius21±2[8] R☉
Luminosity340[3] L☉
Surface gravity (log g)3.11[3] cgs
Temperature5,333[3] K
Metallicity [Fe/H]−0.15[3] dex
Rotational velocity (v sin i)10[9] km/s
Age151[7] Myr
Other designations
Sham, Alsahm, α Sge, 5 Sagittae, BD+17°4042, FK5 1133, GC 27215, HD 185758, HIP 96757, HR 7479, SAO 105120, PPM 136737, CCDM J19401+1801A, WDS J19401+1801A[10]
Database references
SIMBADdata

This is an evolved bright giant with a stellar classification of G1 II.[3] It is 151[7] million years old with 4[7] times the mass of the Sun and has expanded to around 21[8] times the Sun's radius. It is radiating 340 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,333 K.[3] There is an X-ray source within 12″ of these coordinates.[14]

The evolutionary state of Alpha Sagittae is unclear. Its temperature and luminosity place it within the Hertzsprung gap, a region of the H-R diagram where stars more massive than the sun are evolving rapidly away from the main sequence towards becoming red giants. However, the chemical composition of its surface indicates that it has already experienced the first dredge-up of fusion products that occurs soon after a star reaches the red giant branch. It also lies within the Cepheid instability strip, but is not a Cepheid variable.[15] It belongs to a small group of known stars that have been called carbon-deficient red giants and may have experienced binary mass exchanges.[16]

Nomenclature edit

This star bore the traditional name Sham (or Alsahm), which derives from the Arabic word سهم sahm, meaning "arrow", the name formerly having been applied to the whole constellation. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[17] to catalogue and standardize proper names for stars. The WGSN approved the name Sham for this star on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.[12]

In Chinese, 左旗 (Zuǒ Qí), meaning Left Flag, refers to an asterism consisting of Alpha Sagittae, Beta Sagittae, Delta Sagittae, Zeta Sagittae, Gamma Sagittae, 13 Sagittae, 11 Sagittae, 14 Sagittae and Rho Aquilae. Consequently, the Chinese name for Alpha Sagittae itself is 左旗一 (Zuǒ Qí yī, English: the First Star of Left Flag).[18]

References edit

  1. ^ a b c d e 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.
  2. ^ a b Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
  3. ^ a b c d e f g Mallik, Sushma V. (December 1999). "Lithium abundance and mass". Astronomy and Astrophysics. 352: 495–507. Bibcode:1999A&A...352..495M.
  4. ^ 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.
  5. ^ a b Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. (2008). "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants". Astronomy and Astrophysics. 480 (1): 91–101. arXiv:0712.1370. Bibcode:2008A&A...480...91S. doi:10.1051/0004-6361:20078788. S2CID 16602121.
  6. ^ Kovtyukh, V. V.; Gorlova, N. I.; Belik, S. I. (2012). "Accurate luminosities from the oxygen λ7771-4 Å triplet and the fundamental parameters of F-G supergiants". Monthly Notices of the Royal Astronomical Society. 423 (4): 3268. arXiv:1204.4115. Bibcode:2012MNRAS.423.3268K. doi:10.1111/j.1365-2966.2012.21117.x. S2CID 118683158.
  7. ^ a b c d Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (2008). "Stellar Parameters and Elemental Abundances of Late-G Giants". Publications of the Astronomical Society of Japan. 60 (4): 781. arXiv:0805.2434. Bibcode:2008PASJ...60..781T. doi:10.1093/pasj/60.4.781. S2CID 16258166.
  8. ^ a b van Belle, G. T.; et al. (2009). "Supergiant temperatures and linear radii from near-infrared interferometry". Monthly Notices of the Royal Astronomical Society. 394 (4): 1925. arXiv:0811.4239. Bibcode:2009MNRAS.394.1925V. doi:10.1111/j.1365-2966.2008.14146.x. S2CID 118372600.
  9. ^ Böhm-Vitense, Erika (November 2004). "Rotation and Lithium Surface Abundances, Revisited". The Astronomical Journal. 128 (5): 2435−2442. Bibcode:2004AJ....128.2435B. doi:10.1086/425053.
  10. ^ "5 Sge". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-03-30.
  11. ^ 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.
  12. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  13. ^ 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.
  14. ^ Greiner, J.; Richter, G. A. (March 2015). "Optical counterparts of ROSAT X-ray sources in two selected fields at low vs. high Galactic latitudes". Astronomy & Astrophysics. 575: 67. arXiv:1408.5529. Bibcode:2015A&A...575A..42G. doi:10.1051/0004-6361/201322844. S2CID 59501196. A42.
  15. ^ Vanture, Andrew D.; Wallerstein, George (1999). "Carbon, Nitrogen, and Oxygen Abundances of Selected Stars in the Hertzsprung Gap". Publications of the Astronomical Society of the Pacific. 111 (755): 84. Bibcode:1999PASP..111...84V. doi:10.1086/316306.
  16. ^ Bond, Howard E. (2019). "Carbon-deficient Red Giants". The Astrophysical Journal. 887 (1): 12. arXiv:1910.06256. Bibcode:2019ApJ...887...12B. doi:10.3847/1538-4357/ab4e13. S2CID 204512549.
  17. ^ "IAU Working Group on Star Names (WGSN)". International Astronomical Union. Retrieved 22 May 2016.
  18. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 3 日

January 01, 1970
alpha, sagittae, formally, named, sham, single, star, northern, constellation, sagitta, bayer, designation, which, latinized, from, sagittae, abbreviated, alpha, visible, naked, yellow, hued, star, with, apparent, visual, magnitude, despite, name, this, bright. Alpha Sagittae formally named Sham ˈ ʃ ae m 11 12 is a single 13 star in the northern constellation of Sagitta Alpha Sagittae is the Bayer designation which is latinized from a Sagittae and abbreviated Alpha Sge or a Sge It is visible to the naked eye as a yellow hued star with an apparent visual magnitude of 4 38 2 Despite the name this is not the brightest star in the constellation that distinction belongs to Gamma Sagittae Based upon parallax measurements Alpha Sagittae is approximately 382 light years from the Sun It is moving further away from the Earth with a heliocentric radial velocity of 1 7 km s 5 a SagittaeLocation of a Sagittae circled Observation dataEpoch J2000 0 Equinox J2000 0 ICRS Constellation Sagitta Right ascension 19h 40m 05 7918540977s 1 Declination 18 00 50 004597761 1 Apparent magnitude V 4 38 2 Characteristics Evolutionary stage bright giant Spectral type G1 II 3 B V color index 0 777 0 014 4 AstrometryRadial velocity Rv 1 72 0 16 5 km sProper motion m RA 14 630 0 257 1 mas yr Dec 20 160 0 276 1 mas yrParallax p 8 5307 0 1848 mas 1 Distance382 8 ly 117 3 pc Absolute magnitude MV 0 96 6 DetailsMass4 11 7 M Radius21 2 8 R Luminosity340 3 L Surface gravity log g 3 11 3 cgsTemperature5 333 3 KMetallicity Fe H 0 15 3 dexRotational velocity v sin i 10 9 km sAge151 7 Myr Other designationsSham Alsahm a Sge 5 Sagittae BD 17 4042 FK5 1133 GC 27215 HD 185758 HIP 96757 HR 7479 SAO 105120 PPM 136737 CCDM J19401 1801A WDS J19401 1801A 10 Database referencesSIMBADdata This is an evolved bright giant with a stellar classification of G1 II 3 It is 151 7 million years old with 4 7 times the mass of the Sun and has expanded to around 21 8 times the Sun s radius It is radiating 340 times the Sun s luminosity from its enlarged photosphere at an effective temperature of 5 333 K 3 There is an X ray source within 12 of these coordinates 14 The evolutionary state of Alpha Sagittae is unclear Its temperature and luminosity place it within the Hertzsprung gap a region of the H R diagram where stars more massive than the sun are evolving rapidly away from the main sequence towards becoming red giants However the chemical composition of its surface indicates that it has already experienced the first dredge up of fusion products that occurs soon after a star reaches the red giant branch It also lies within the Cepheid instability strip but is not a Cepheid variable 15 It belongs to a small group of known stars that have been called carbon deficient red giants and may have experienced binary mass exchanges 16 Nomenclature editThis star bore the traditional name Sham or Alsahm which derives from the Arabic word سهم sahm meaning arrow the name formerly having been applied to the whole constellation In 2016 the International Astronomical Union organized a Working Group on Star Names WGSN 17 to catalogue and standardize proper names for stars The WGSN approved the name Sham for this star on 12 September 2016 and it is now so included in the List of IAU approved Star Names 12 In Chinese 左旗 Zuǒ Qi meaning Left Flag refers to an asterism consisting of Alpha Sagittae Beta Sagittae Delta Sagittae Zeta Sagittae Gamma Sagittae 13 Sagittae 11 Sagittae 14 Sagittae and Rho Aquilae Consequently the Chinese name for Alpha Sagittae itself is 左旗一 Zuǒ Qi yi English the First Star of Left Flag 18 References edit a b c d e 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 a b Hog E et al 2000 The Tycho 2 catalogue of the 2 5 million brightest stars Astronomy and Astrophysics 355 L27 L30 Bibcode 2000A amp A 355L 27H a b c d e f g Mallik Sushma V December 1999 Lithium abundance and mass Astronomy and Astrophysics 352 495 507 Bibcode 1999A amp A 352 495M 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 Soubiran C Bienayme O Mishenina T V Kovtyukh V V 2008 Vertical distribution of Galactic disk stars IV AMR and AVR from clump giants Astronomy and Astrophysics 480 1 91 101 arXiv 0712 1370 Bibcode 2008A amp A 480 91S doi 10 1051 0004 6361 20078788 S2CID 16602121 Kovtyukh V V Gorlova N I Belik S I 2012 Accurate luminosities from the oxygen l7771 4 A triplet and the fundamental parameters of F G supergiants Monthly Notices of the Royal Astronomical Society 423 4 3268 arXiv 1204 4115 Bibcode 2012MNRAS 423 3268K doi 10 1111 j 1365 2966 2012 21117 x S2CID 118683158 a b c d Takeda Yoichi Sato Bun ei Murata Daisuke 2008 Stellar Parameters and Elemental Abundances of Late G Giants Publications of the Astronomical Society of Japan 60 4 781 arXiv 0805 2434 Bibcode 2008PASJ 60 781T doi 10 1093 pasj 60 4 781 S2CID 16258166 a b van Belle G T et al 2009 Supergiant temperatures and linear radii from near infrared interferometry Monthly Notices of the Royal Astronomical Society 394 4 1925 arXiv 0811 4239 Bibcode 2009MNRAS 394 1925V doi 10 1111 j 1365 2966 2008 14146 x S2CID 118372600 Bohm Vitense Erika November 2004 Rotation and Lithium Surface Abundances Revisited The Astronomical Journal 128 5 2435 2442 Bibcode 2004AJ 128 2435B doi 10 1086 425053 5 Sge SIMBAD Centre de donnees astronomiques de Strasbourg Retrieved 2019 03 30 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 Naming Stars IAU org Retrieved 16 December 2017 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 Greiner J Richter G A March 2015 Optical counterparts of ROSAT X ray sources in two selected fields at low vs high Galactic latitudes Astronomy amp Astrophysics 575 67 arXiv 1408 5529 Bibcode 2015A amp A 575A 42G doi 10 1051 0004 6361 201322844 S2CID 59501196 A42 Vanture Andrew D Wallerstein George 1999 Carbon Nitrogen and Oxygen Abundances of Selected Stars in the Hertzsprung Gap Publications of the Astronomical Society of the Pacific 111 755 84 Bibcode 1999PASP 111 84V doi 10 1086 316306 Bond Howard E 2019 Carbon deficient Red Giants The Astrophysical Journal 887 1 12 arXiv 1910 06256 Bibcode 2019ApJ 887 12B doi 10 3847 1538 4357 ab4e13 S2CID 204512549 IAU Working Group on Star Names WGSN International Astronomical Union Retrieved 22 May 2016 in Chinese AEEA Activities of Exhibition and Education in Astronomy 天文教育資訊網 2006 年 7 月 3 日 Retrieved from https en wikipedia org w index php title Alpha Sagittae amp oldid 1186943121, wikipedia, wiki, book, books, library,

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