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Gamma Capricorni

March 11, 2023

Gamma Capricorni or γ Capricorni, formally named Nashira (/ˈnæʃɪrə/),[12] is a giant star in the constellation of Capricornus. Based on parallax measurements obtained during the Hipparcos mission, it is located at a distance of approximately 157 light-years from the Sun. The star is drifting closer with a radial velocity of −31 km/s.[6] It is 2.56 degrees south of the ecliptic, so it can be occulted by the Moon, and (rarely) by planets.

γ Capricorni
Location of γ Capricorni (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Capricornus
Right ascension 21h 40m 05.45648s[1]
Declination −16° 39′ 44.307184″[1]
Apparent magnitude (V) +3.67[2]
Characteristics
Spectral type kF0hF1VmF2[3]
U−B color index +0.22[4]
B−V color index +0.32[4]
Variable type α2 CVn[5]
Astrometry
Radial velocity (Rv)−31.2±0.5[6] km/s
Proper motion (μ) RA: +187.56[1] mas/yr
Dec.: −22.45[1] mas/yr
Parallax (π)20.77 ± 0.72 mas[1]
Distance157 ± 5 ly
(48 ± 2 pc)
Absolute magnitude (MV)+2.60[7]
Details
Mass2.44[8] M☉
Radius2.35[8] R☉
Surface gravity (log g)3.69[8] cgs
Temperature7,520[9] K
Metallicity [Fe/H]+0.5[9] dex
Rotational velocity (v sin i)40[10] km/s
Other designations
Nashira, Gamma Cap, Gam Cap, γ Cap, 40 Capricorni, BD−17°6340, FK5 812, GJ 4209, HD 206088, HIP 106985, HR 8278, SAO 164560[11]
Database references
SIMBADdata

Nomenclature

γ Capricorni (Latinised to Gamma Capricorni) is the star's Bayer designation.

It bore the traditional name Nashira, derived from the Arabic سعد ناشرة sa'd nashirah "the lucky one" or "bearer of good news". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[13] to catalogue and standardize proper names for stars. The WGSN approved the name Nashira for this star on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.[12]

In Chinese, 壘壁陣 (Lěi Bì Zhèn), meaning Line of Ramparts, refers to an asterism consisting of Gamma Capricorni, Kappa Capricorni, Epsilon Capricorni, Delta Capricorni, Iota Aquarii, Sigma Aquarii, Lambda Aquarii, Phi Aquarii, 27 Piscium, 29 Piscium, 33 Piscium and 30 Piscium.[14] Consequently, the Chinese name for Gamma Capricorni itself is 壘壁陣三 (Lěi Bì Zhèn sān, English: the Third Star of Line of Ramparts).[15]

Namesake

Nashira (AK-85) was a United States Navy ship, though it was never commissioned and never bore the USS designation.[16][17]

Properties

γ Capricorni is classified as a hot chemically peculiar Am star with a mean apparent magnitude of +3.67. The spectrum displays abundance anomalies of the elements strontium, chromium, and europium.[8] It was first classified as an Am star in 1965 by K. Osawa, but in 1974 C. Bertaud and M. Floquet found it to be an Ap star with a strontium abundance anomaly. In 1998, F. A. Catalano and associates found a slight variability in the infrared J band with a period of 2.78 days, which suggests the Ap classification is correct. However, no magnetic field is detected, which points to the Am classification, as does the infrared spectrum. The star displays large radial velocity variations, which could be explained by star spots and rotation. Alternatively it may be a double-lined spectroscopic binary viewed from nearly pole-on.[18]

This star is classified as an α2 Canum Venaticorum type variable star and its brightness varies by 0.03 magnitudes.[5] It has 2.44 times the mass and 2.35 times the radius of the Sun.[8] O. J. Eggen included it as a member of the Hyades Stream.[7]

References

  1. ^ a b c d e 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.
  2. ^ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. ^ Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
  4. ^ a b Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99. Bibcode:1966CoLPL...4...99J.
  5. ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  6. ^ a b Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  7. ^ a b Eggen, Olin J. (July 1998), "The Age Range of Hyades Stars", The Astronomical Journal, 116 (1): 284–292, Bibcode:1998AJ....116..284E, doi:10.1086/300413.
  8. ^ a b c d e Glagolevskij, Yu. V. (January 2019). "On Properties of Main Sequence Magnetic Stars". Astrophysical Bulletin. 74 (1): 66–79. Bibcode:2019AstBu..74...66G. doi:10.1134/S1990341319010073. S2CID 149900274.
  9. ^ a b Burkhart, C.; Coupry, M. F. (September 1991). "The A and Am-Fm stars. I - The abundances of Li, Al, Si, and Fe". Astronomy and Astrophysics. 249 (1): 205–216. Bibcode:1991A&A...249..205B.
  10. ^ Royer, F.; Grenier, S.; Baylac, M.-O.; Gómez, A. E.; Zorec, J. (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.
  11. ^ "gam Cap". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-06-20.
  12. ^ a b "Naming Stars". IAU.org. Retrieved 7 March 2018.
  13. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
  14. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  15. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 January 30, 2011, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  16. ^ . Naval History & Heritage Command. Archived from the original on 3 January 2015.
  17. ^ "NavSource Online: Service Ship Photo Archive: AK-85 Nashira". navsource.org. Retrieved 28 December 2016.
  18. ^ Carrier, F.; North, P.; Udry, S.; Babel, J. (October 2002). "Multiplicity among chemically peculiar stars. II. Cool magnetic Ap stars". Astronomy and Astrophysics. 394: 151–169. arXiv:astro-ph/0208082. Bibcode:2002A&A...394..151C. doi:10.1051/0004-6361:20021122. S2CID 14223227.

External links

March 11, 2023
gamma, capricorni, capricorni, formally, named, nashira, giant, star, constellation, capricornus, based, parallax, measurements, obtained, during, hipparcos, mission, located, distance, approximately, light, years, from, star, drifting, closer, with, radial, v. Gamma Capricorni or g Capricorni formally named Nashira ˈ n ae ʃ ɪ r e 12 is a giant star in the constellation of Capricornus Based on parallax measurements obtained during the Hipparcos mission it is located at a distance of approximately 157 light years from the Sun The star is drifting closer with a radial velocity of 31 km s 6 It is 2 56 degrees south of the ecliptic so it can be occulted by the Moon and rarely by planets g CapricorniLocation of g Capricorni circled Observation dataEpoch J2000 0 Equinox J2000 0 ICRS Constellation CapricornusRight ascension 21h 40m 05 45648s 1 Declination 16 39 44 307184 1 Apparent magnitude V 3 67 2 CharacteristicsSpectral type kF0hF1VmF2 3 U B color index 0 22 4 B V color index 0 32 4 Variable type a2 CVn 5 AstrometryRadial velocity Rv 31 2 0 5 6 km sProper motion m RA 187 56 1 mas yr Dec 22 45 1 mas yrParallax p 20 77 0 72 mas 1 Distance157 5 ly 48 2 pc Absolute magnitude MV 2 60 7 DetailsMass2 44 8 M Radius2 35 8 R Surface gravity log g 3 69 8 cgsTemperature7 520 9 KMetallicity Fe H 0 5 9 dexRotational velocity v sin i 40 10 km sOther designationsNashira Gamma Cap Gam Cap g Cap 40 Capricorni BD 17 6340 FK5 812 GJ 4209 HD 206088 HIP 106985 HR 8278 SAO 164560 11 Database referencesSIMBADdata Contents 1 Nomenclature 1 1 Namesake 2 Properties 3 References 4 External linksNomenclature Editg Capricorni Latinised to Gamma Capricorni is the star s Bayer designation It bore the traditional name Nashira derived from the Arabic سعد ناشرة sa d nashirah the lucky one or bearer of good news In 2016 the International Astronomical Union organized a Working Group on Star Names WGSN 13 to catalogue and standardize proper names for stars The WGSN approved the name Nashira for this star on 21 August 2016 and it is now so included in the List of IAU approved Star Names 12 In Chinese 壘壁陣 Lei Bi Zhen meaning Line of Ramparts refers to an asterism consisting of Gamma Capricorni Kappa Capricorni Epsilon Capricorni Delta Capricorni Iota Aquarii Sigma Aquarii Lambda Aquarii Phi Aquarii 27 Piscium 29 Piscium 33 Piscium and 30 Piscium 14 Consequently the Chinese name for Gamma Capricorni itself is 壘壁陣三 Lei Bi Zhen san English the Third Star of Line of Ramparts 15 Namesake Edit Nashira AK 85 was a United States Navy ship though it was never commissioned and never bore the USS designation 16 17 Properties Editg Capricorni is classified as a hot chemically peculiar Am star with a mean apparent magnitude of 3 67 The spectrum displays abundance anomalies of the elements strontium chromium and europium 8 It was first classified as an Am star in 1965 by K Osawa but in 1974 C Bertaud and M Floquet found it to be an Ap star with a strontium abundance anomaly In 1998 F A Catalano and associates found a slight variability in the infrared J band with a period of 2 78 days which suggests the Ap classification is correct However no magnetic field is detected which points to the Am classification as does the infrared spectrum The star displays large radial velocity variations which could be explained by star spots and rotation Alternatively it may be a double lined spectroscopic binary viewed from nearly pole on 18 This star is classified as an a2 Canum Venaticorum type variable star and its brightness varies by 0 03 magnitudes 5 It has 2 44 times the mass and 2 35 times the radius of the Sun 8 O J Eggen included it as a member of the Hyades Stream 7 References Edit a b c d e 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 Ducati J R 2002 VizieR Online Data Catalog Catalogue of Stellar Photometry in Johnson s 11 color system CDS ADC Collection of Electronic Catalogues 2237 Bibcode 2002yCat 2237 0D Abt Helmut A Morrell Nidia I 1995 The Relation between Rotational Velocities and Spectral Peculiarities among A Type Stars Astrophysical Journal Supplement 99 135 Bibcode 1995ApJS 99 135A doi 10 1086 192182 a b Johnson H L Iriarte B Mitchell R I Wisniewskj W Z 1966 UBVRIJKL photometry of the bright stars Communications of the Lunar and Planetary Laboratory 4 99 99 Bibcode 1966CoLPL 4 99J a b Samus N N Durlevich O V et al 2009 VizieR Online Data Catalog General Catalogue of Variable Stars Samus 2007 2013 VizieR On line Data Catalog B GCVS Originally Published in 2009yCat 102025S 1 Bibcode 2009yCat 102025S a b Gontcharov G A November 2006 Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system Astronomy Letters 32 11 759 771 arXiv 1606 08053 Bibcode 2006AstL 32 759G doi 10 1134 S1063773706110065 S2CID 119231169 a b Eggen Olin J July 1998 The Age Range of Hyades Stars The Astronomical Journal 116 1 284 292 Bibcode 1998AJ 116 284E doi 10 1086 300413 a b c d e Glagolevskij Yu V January 2019 On Properties of Main Sequence Magnetic Stars Astrophysical Bulletin 74 1 66 79 Bibcode 2019AstBu 74 66G doi 10 1134 S1990341319010073 S2CID 149900274 a b Burkhart C Coupry M F September 1991 The A and Am Fm stars I The abundances of Li Al Si and Fe Astronomy and Astrophysics 249 1 205 216 Bibcode 1991A amp A 249 205B Royer F Grenier S Baylac M O Gomez A E Zorec J 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 gam Cap SIMBAD Centre de donnees astronomiques de Strasbourg Retrieved 2021 06 20 a b Naming Stars IAU org Retrieved 7 March 2018 IAU Working Group on Star Names WGSN International Astronomical Union retrieved 22 May 2016 in Chinese 中國星座神話 written by 陳久金 Published by 台灣書房出版有限公司 2005 ISBN 978 986 7332 25 7 in Chinese 香港太空館 研究資源 亮星中英對照表 Archived January 30 2011 at the Wayback Machine Hong Kong Space Museum Accessed on line November 23 2010 Ship Naming in the United States Navy Naval History amp Heritage Command Archived from the original on 3 January 2015 NavSource Online Service Ship Photo Archive AK 85 Nashira navsource org Retrieved 28 December 2016 Carrier F North P Udry S Babel J October 2002 Multiplicity among chemically peculiar stars II Cool magnetic Ap stars Astronomy and Astrophysics 394 151 169 arXiv astro ph 0208082 Bibcode 2002A amp A 394 151C doi 10 1051 0004 6361 20021122 S2CID 14223227 External links EditKaler James B Nashira STARS Retrieved 2021 06 21 Retrieved from https en wikipedia org w index php title Gamma Capricorni amp oldid 1136214847, wikipedia, wiki, book, books, library,

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