{{Short description|Star in the constellation Aquila}} {{Starbox begin | name=γ Aquilae }} {{Starbox image | image= {{Location mark |image=Aquila constellation map.svg|alt=|float=center|width=240 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=γ Aquilae |x=468|y=290 }} | caption=Location of γ Aquilae (circled) }} {{Starbox observe | epoch = J2000 | ra = {{RA|19|46|15.58029}}<ref name=aaa474_2_653/> | dec = {{DEC|+10|36|47.7408}}<ref name=aaa474_2_653/> | appmag_v = +2.712<ref name=saaoc8_59/> | constell = Aquila }} {{Starbox character | class = K3 II<ref name=araa11_29/> | b-v = +1.500<ref name=saaoc8_59/> | u-b = +1.720<ref name=saaoc8_59/> | variable = }} {{Starbox astrometry | radial_v = −2.79<ref name=aaa430_165/> | prop_mo_ra = +16.99 | prop_mo_dec = −2.98 | pm_footnote = <ref name=aaa474_2_653/> | parallax = 8.26 | p_error = 0.17 | parallax_footnote = <ref name=aaa474_2_653/> | absmag_v = {{val|-3.38|0.24|0.22}}<ref name=aj135_3_892/> }} {{Starbox detail | source = <ref name=Baines_et_al_2017/> | mass = {{val|3.51|0.23}} | radius = {{val|91.81|2.19|2.12}} | luminosity = {{val|2,146|139|fmt=commas}} | temperature = {{val|4,098|56|fmt=commas}} | gravity = 1.52 | metal_fe = −0.29<ref name=apjss74/> | rotational_velocity = 8<ref name=csrv/> | age_myr = {{val|270|40}} }} {{Starbox catalog | names = {{odlist | name=Tarazed, Reda | F=50 Aql | B=Gamma Aql, γ Aql | BD=+10 4043 | FK5=741 | HD=186791 | HIP=97278 | HR=7525 | SAO=105223 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = HD+186791 | ARICNS = }} {{Starbox end}}
'''Gamma Aquilae''' is a star in the constellation of Aquila. Its name is a Bayer designation that is Latinized from '''γ Aquilae''', and abbreviated gamma Aql or γ Aql. The star is formally known as '''Tarazed''', pronounced {{IPAc-en|ˈ|t|ær|ə|z|ɛ|d}}.<ref name="IAU-CSN"/> It has an apparent visual magnitude of 2.712,<ref name=saaoc8_59/> making it readily visible to the naked eye at night. Parallax measurements place it at a distance of {{Convert|395|ly|pc|abbr=off|lk=on}} from the Sun.<ref name=aaa474_2_653/> The star is drifting closer to the Sun with a radial velocity of −2.8 km/s.<ref name=aaa430_165/>
==Properties== [[File:Altair-Tarazed-heic0720c.jpg|Position of γ Aquilae relative to Altair (center)|thumb|left|upright]] Gamma Aquilae is a relatively young star with an age of about 270 million years.<ref name=Baines_et_al_2017/> Nevertheless, it has reached a stage of its evolution where it has consumed the hydrogen at its core and expanded into what is termed a bright giant star, with a stellar classification of K3 II.<ref name=araa11_29/> The star is now burning helium into carbon in its core. After it has finished generating energy through nuclear fusion, Gamma Aquilae will become a white dwarf.<ref name=kaler/>
The star has an estimated 3.5 times the mass of the Sun and has expanded to 92 times the Sun's radius. It is radiating over 2,100 times the luminosity of the Sun. An effective temperature of {{val|4,098|u=K|fmt=commas}}<ref name=Baines_et_al_2017/> in its outer envelope gives it the orange hue typical of K-type stars.<ref name=csiro/> A 1991 catalogue of photometry reported that Gamma Aquilae showed some variation in its brightness, but this has not been confirmed.<ref name=sternberg/> It is a known source of X-ray emission, which is most likely being emitted by a hot corona.<ref name=Reimers_Schmitt_1996/>
Gamma Aquilae is located just 7' from the center of an emission nebula, which has been first reported in 2023 by Stefan Ziegenbalg. The star is unlikely to be the ionization source of this nebula.<ref name=Ziegenbalg_2023/>
==Nomenclature== ''γ Aquilae'' (Latinised to ''Gamma Aquilae'') is the star's Bayer designation.
It bore the traditional name ''Tarazed'',<ref name=kaler/> which may derive from the Persian شاهين ترازو ''šāhin tarāzu'' "the beam of the scale", referring to an asterism of the Scale, Alpha, Beta and Gamma Aquilae. (Persian ''šāhīn'' means "royal falcon", "beam", and "pointer", and gave its name (as "falcon") to Beta Aquilae.) In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN"/> to catalogue and standardize proper names for stars. The WGSN approved the name ''Tarazed'' for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.<ref name="IAU-CSN"/> In the catalogue of stars in the ''Calendarium of Al Achsasi Al Mouakket'', this star was designated ''Menkib al Nesr'' (''منكب ألنسر'' - ''mankib al-nasr''), which was translated into Latin as ''Humerus Vulturis'', meaning 'the eagle's shoulder'.<ref name=Knobel_1895/>
In Chinese astronomy, {{lang|zh|河鼓}} ({{lang|zh-Latn|Hé Gŭ}}), meaning ''River Drum'', refers to an asterism consisting of Gamma Aquilae, Beta Aquilae and Altair.<ref>{{in lang|zh}} ''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}}.</ref> Consequently, the Chinese name for Gamma Aquilae itself is {{lang|zh|河鼓三}} ({{lang|zh-Latn|Hé Gŭ sān}}, {{langx|en|the Third Star of River Drum}}).<ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_t_z.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive |url=https://web.archive.org/web/20100819122914/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_t_z.htm |date=August 19, 2010 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref> In the Chinese folk tale ''The Cowherd and the Weaver Girl'', Gamma Aquilae and Beta Aquilae are the children of Niulang (牛郎, The Cowherd, Altair) and Zhinü (織女, The Princess, Vega).
The Koori people of Victoria knew Beta and Gamma Aquilae as the black swan wives of ''Bunjil'' (Altair), the wedge-tailed eagle.<ref name=Mudrooroo_1994/>
==References== {{Reflist|30em|refs=
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<ref name=SIMBAD>{{cite simbad | title=gam Aql | access-date=2012-01-09 }}</ref>
<ref name=kaler>{{citation | first1=James B. | last1=Kaler | title=TARAZED (Gamma Aquilae) | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/tarazed.html | access-date=2012-01-10 }}</ref>
<ref name=csiro>{{citation |title=The Colour of Stars |date=December 21, 2004 |work=Australia Telescope, Outreach and Education |publisher=Commonwealth Scientific and Industrial Research Organisation |url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |access-date=2012-01-16 |url-status=dead |archive-url=https://web.archive.org/web/20120318151427/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |archive-date=2012-03-18 }}</ref>
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<ref name=Baines_et_al_2017>{{citation | postscript=. | title=Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer | display-authors=1 | last1=Baines | first1=E. | last2=Schmitt | first2=H. R. | last3=Zavala | first3=R. T. | last4=Hutter | first4=D. | last5=van Belle | first5=G. T. | journal=The Astronomical Journal | volume=155 | issue=1 | pages=30 | year=2017 | bibcode=2018AJ....155...30B | doi=10.3847/1538-3881/aa9d8b | arxiv=1712.08109 | s2cid=119427037 | doi-access=free }}</ref>
<ref name="IAU-CSN">{{citation | postscript=. | title=IAU Catalog of Star Names | publisher=International Astronomical Union | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | access-date=28 July 2016}}</ref>
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<ref name=Ziegenbalg_2023>{{citation | postscript=. | title=Discovery of an Emission Nebula in Direction of γ Aql | last=Ziegenbalg |first=Stefan | journal=Research Notes of the AAS | language=en | volume=7 | issue=12 | pages=274 | date=December 2023 | doi=10.3847/2515-5172/ad168b | doi-access=free | bibcode=2023RNAAS...7..274Z | issn=2515-5172}}</ref>
<ref name=Reimers_Schmitt_1996>{{citation | postscript=. | title=ROSAT X-Ray Observations of Hybrid Stars | last1=Reimers | first1=D. | last2=Schmitt | first2=J. H. M. M. | journal=Astronomy and Astrophysics | volume=310 | pages=813–824 | date=June 1996 | bibcode=1992ApJ...392L..55R }}</ref>
}}
==External links== * [http://www.constellationsofwords.com/stars/Tarazed.html Tarazed] * [https://web.archive.org/web/20090713200346/http://www.scenta.co.uk/tcaep/nonxml/astronomy/constellations/19460060.htm Tarazed] * [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=HR&HR=7525 HR 7525] * [http://aladin.u-strasbg.fr/AladinPreview?-c=NAME+TARAZED&ident=NAME+TARAZED&submit=Aladin+previewer Image Gamma Aquilae]
{{Stars of Aquila}} {{Authority control}}
<!-- Properties --> Category:K-type bright giants Category:Suspected variables Category:Astronomical X-ray sources <!-- Other --> Category:Aquila (constellation) Aquilae, Gamma 7525 Category:Durchmusterung objects Aquilae, 50 186791 097278 Tarazed Category:Horizontal-branch stars