Gamma Aquarii

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Template:Short description

Gamma Aquarii
Template:Location mark
Location of γ Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 3.849[2]
Characteristics
Spectral type A0 V[3]
U−B Template:Engvar −0.092[2]
B−V Template:Engvar −0.060[2]
Astrometry
Radial velocity (Rv)Template:Val[4] km/s
Proper motion (μ) RA: +129.53 mas/yr[1]
Dec.: +7.77 mas/yr[1]
Parallax (π)19.92±1.04 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)+0.10[5]
Details
Aa
MassTemplate:Val[6] Template:Solar mass
Radius2.7[6] Template:Solar radius
Surface gravity (log g)Template:Val[7] cgs
TemperatureTemplate:Val[7] K
Metallicity [Fe/H]+0.30[8] dex
Rotational velocity (v sin i)80[9] km/s
AgeTemplate:Val[6] Myr
Ab
Mass0.56[6] Template:Solar mass
Radius0.5[6] Template:Solar radius
Temperature3,900[6] K
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[10]
Database references
SIMBADdata

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Gamma Aquarii, or γ Aquarii, is a binary star system[6] in the constellation of Aquarius. It has an apparent visual magnitude of 3.849,[2] making it one of the brighter members of the constellation. Based upon parallax measurements, this star is located at a distance of Template:Convert.[1] It is drifting closer to Earth with a radial velocity of −16 km/s.[4] It is a candidate member of the Hyades Supercluster.[5]

The two components are designated Gamma Aquarii Aa, formally called Sadachbia Template:IPAc-en,[11] and Ab.

Nomenclature

γ Aquarii, Latinised to Gamma Aquarii, is the system's Bayer designation. WDS J22217-0123 A is its designation in the Washington Double Star Catalog.

It bore the traditional name Sadachbia, from an Arabic expression سعد الأخبية (sa‘d al-’axbiyah), meaning "luck of the homes (tents)". In Hindi it is also called Satabhishaj (a hundred physicians); it is called Sadhayam in Tamil. In the catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, this star was designated Aoul al Achbiya (أول ألأجبية - awwil al ahbiyah), which was translated into Latin as Prima Tabernaculorum, meaning the first of luck of the homes (tents).[12] 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 Sadachbia for the component WDS J22217-0123 Aa on 21 August 2016, and it is now so included in the List of IAU-approved Star Names.[11]

This star, along with Pi Aquarii (Seat), Zeta Aquarii (Sadaltager / Achr al Achbiya) and Eta Aquarii (Hydria), were al Aḣbiyah الأخبية "the Tent".[14][15][16]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Tomb, refers to an asterism consisting of Gamma Aquarii, Zeta Aquarii, Eta Aquarii and Pi Aquarii.[17] Consequently, the Chinese name for Gamma Aquarii itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx).[18]

Properties

In 1978 through 1984, H. A. McAlister listed this as a spectroscopic binary star system that is unresolved by speckle interferometry,[19][20] and it is listed as such in the 1991 revision of the Bright Star Catalogue.[21] In 2008, P. P. Eggleton and A. A. Tokovinin listed it as a single star in their catalogue of multiplicity.[22] However, in 2024, a companion star to Gamma Aquarii was detected by interferometric observations.[6]

The primary is an A-type main sequence star with a stellar classification of A0 V,[3] around 2.7 times larger and more massive than the Sun.[6] It was a candidate Lambda Boötis star, suggesting it may have accreted low-metallicity circumstellar gas some time in the past.[23] But it has since been excluded.[24] The star is spinning relatively rapidly with a projected rotational velocity of 80 km s−1.[9] This value gives a lower bound on the actual azimuthal velocity along the star's equator. The outer atmosphere of Gamma Aquarii is radiating energy at an effective temperature of 10,500 K,[8] which is nearly double the temperature at the surface of the Sun. This heat is what gives Gamma Aquarii the white-hot glow of an A-type star.[25]

The secondary component is a low-mass star which has around 0.56 times the mass and half the radius of the Sun. Its effective temperature of 3,900 K[6] gives it the orange hue typical of late K-type stars.[25] This secondary could explain the X-ray emission detected from this system with the ROSAT X-ray telescope.[6] Located 1.9 astronomical units from each other, both stars take around a year to orbit the system's center of mass.[6]

References

Template:Reflist

External links

Template:Stars of Aquarius

  1. ↑ a b c d e Cite error: Invalid <ref> tag; no text was provided for refs named aaa474_2_653
  2. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named saaoc8_59
  3. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named aj74_375
  4. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Gontcharov2006
  5. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Eggen1998
  6. ↑ a b c d e f g h i j k l Cite error: Invalid <ref> tag; no text was provided for refs named waisberg
  7. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named David2015
  8. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named apj155_537
  9. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named aaa463_2_671
  10. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named SIMBAD
  11. ↑ a b Script error: No such module "citation/CS1".
  12. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named mnras55_429
  13. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named WGSN
  14. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named pa52_3_12
  15. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named allen1963f
  16. ↑ Gamma Aqr as Aoul al Achbiya or Prima Tabernaculorum (the first of luck of the homes or tents), Pi Aquarii as Wasat al Achbiya or Media Tabernaculorum (the middle of luck of the homes or tents) and Zeta Aquarii as Achr al Achbiya or Postrema Tabernaculorum (the end of luck of the homes or tents). Eta Aquarii should be designated as al Achbiya consistently, but it was not designated as the Arabic name except the name Hydria (Greek) or Deli (Hebrew)
  17. ↑ Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.
  18. ↑ Template:In lang 香港太空館 - 研究資源 - 亮星中英對照表 Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.
  19. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named McAlister1978
  20. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Hartkopf_McAlister_1984
  21. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Hoffleit1991
  22. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Eggleton_Tokovinin_2008
  23. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named mnras269_1_209
  24. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Cheng_et_al_2017
  25. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named csiro
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