Location of ? Aquarii (circled)
Epoch J2000 Equinox J2000
22 h 21 m 39.37542 s 
-01° 23′ 14.4031″ 
3.849  Characteristics
A0 V  U-B
-0.092  B-V
-0.060  Astrometry Radial velocity (R v) -15 km/s  Proper motion (?) RA: +129.53  mas/ yr Dec.: +7.77  mas/ yr Parallax (?) 19.92 ± 1.04  mas Distance 164 ± 9 ly (50 ± 3 pc) Absolute magnitude (M V) +0.10  Details Surface gravity (log g) 4.0  cgs Temperature 10,500  K [Fe/H] Metallicity +0.30  dex Rotational velocity ( v sin i) 80 km/s  Other designations
Sadalachbia, Sadachbia, 48 Aquarii,
 Database references SIMBAD data Gamma Aquarii ( ? Aquarii, abbreviated Gamma Aqr, ? Aqr) is a binary star in the constellation of Aquarius. It has an apparent visual magnitude of 3.849, making it one of the  brighter members of the constellation. Based upon parallax measurements taken during the Hipparcos mission, this star is located at a distance of approximately 164 light-years (50 parsecs) from the Sun. 
Gamma Aquarii is the primary or 'A' component of a
double star designated WDS J22217-0123. The secondary or 'B' component is UCAC2 31430071.  Gamma Aquarii A's two components are therefore designated WDS J22217-0123 Aa and Ab. Gamma Aquarii is traditionally also called  Sadachbia , a name now formally restricted to ? Aqr Aa.  
Nomenclature ? 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 ? ( 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 ( ? - awwil al ahbiyah), which was translated into Latin as Prima Tabernaculorum, meaning the first of luck of the homes (tents). In 2016, the  International Astronomical Union organized a Working Group on Star Names (WGSN) 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. 
This star, along with
Pi Aquarii (Seat), Zeta Aquarii (Sadaltager / Achr al Achbiya) and Eta Aquarii (Hydria), were al A?biyah ? "the Tent".   
Chinese, ( Fén Mù), meaning , refers to an Tomb asterism consisting of Gamma Aquarii, Zeta Aquarii, Eta Aquarii and Pi Aquarii. Consequently, the  Chinese name for Gamma Aquarii itself is ( Fén Mù èr, English: the Second Star of Tomb). 
Gamma Aquarii is a
spectroscopic binary with a period of 58.1 days.
It presents as an
A-type main sequence star with a stellar classification of A0 V, around two and a half times more massive  than the Sun. It is a candidate  Lambda Boötis star, suggesting it may have accreted low- metallicity circumstellar gas some time in the past. It is spinning relatively rapidly with a  projected rotational velocity of . 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, 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. 
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^ 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)
(in Chinese) , written by . Published by ?, 2005, ISBN 978-986-7332-25-7.
(in Chinese) - ? - ? Archived August 18, 2010, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
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