Gamma Cygni

Source: Wikipedia, the free encyclopedia.
For other uses of "Sadr", see Sadr (disambiguation).
Gamma Cygni
Location of γ Cyg (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 20h 22m 13.70184s[1]
Declination +40° 15′ 24.0450″[1]
Apparent magnitude (V) 2.23[2]
Characteristics
Spectral type F8 Iab[3]
U−B color index +0.54[2]
B−V color index +0.67[2]
Variable type suspected[4]
Distance
approx. 1,800 ly
(approx. 560 pc)
Absolute magnitude (MV)−4.54[6]
Details
Myr
HIP 100453, WDS
J20222+4015A.
Database references
SIMBADdata

Gamma Cygni (γ Cygni, abbreviated Gamma Cyg, γ Cyg), officially named Sadr /ˈsædər/,[11][12] is a star in the northern constellation of Cygnus, forming the intersection of an asterism of five stars called the Northern Cross. Based upon parallax measurements obtained during the Hipparcos mission, it is approximately 1,800 light-years (560 parsecs) from the Sun.[1]

It forms the primary or 'A' component of a

multiple star system designated WDS J20222+4015 (the secondary or 'BCD' component is WDS J20222+4015BCD, a close triplet of stars 41" away from γ Cygni[13]
).

Nomenclature

γ Cygni (Latinised to Gamma Cygni) is the star's Bayer designation. WDS J20222+4015A is its designation in the Washington Double Star Catalog.

It bore the traditional name Sadr (also rendered Sadir

multiple systems.[15] It approved the name Sadr for this star (WDS J20222+4015A) on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.[12]

In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Sadr al Dedjadjet, (صدر الدجاجة / ṣadr al-dajāja), which was translated into Latin as Pectus Gallinǣ, meaning the hen's chest.[16]

In

Chinese name for Gamma Cygni itself is 天津一 (Tiān Jīn yī, English: the First Star of Celestial Ford).[18]

Properties

γ Cygni
(center star) and surroundings. Image by Jeff Johnson.

With an

spectrum of this star has served as one of the stable anchor points by which other stars are classified.[19]

Compared to the Sun this is an enormous star, with 14.5 times the

F-type star. Massive stars such as this consume their nuclear fuel much more rapidly than the Sun, so the estimated age of this star is only about 12 million years old.[7]

The

IC 1318
, or the Gamma Cygni region.

Notes

References

  1. ^
    S2CID 18759600
    .
  2. ^
    Bibcode:1966CoLPL...4...99J
  3. ^
    doi:10.1088/0004-6256/140/5/1329
  4. Bibcode:2009yCat....102025S
    .
  5. Bibcode:1967IAUS...30...57E
    .
  6. ^
    S2CID 118683158
    .
  7. ^
    S2CID 119096173
  8. ^ a b Kaler, Jim. "Sadr". stars.astro.illinois.edu. Retrieved 2024-09-21.
  9. ^
    S2CID 111387483
  10. Bibcode:1970CoAsi.239....1B
    .
  11. ISBN 978-1-931559-44-7
    .
  12. ^ a b "Naming Stars". IAU.org. Retrieved 1 March 2018.
  13. ^ "VizieR". vizier.cds.unistra.fr. Retrieved 2024-10-01.
  14. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
  15. ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  16. doi:10.1093/mnras/55.8.429
  17. ISBN 978-986-7332-25-7
    .
  18. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived August 18, 2010, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  19. Bibcode:1993AAS...183.1710G, archived from the original
    on 2019-06-25, retrieved 2012-02-04
Retrieved from "https://en.wikipedia.org/w/index.php?title=Gamma_Cygni&oldid=1256002749"