{{Short description|Multiple star in the constellation Taurus}} {{Starbox begin | name = γ Tauri }} {{Starbox image | image= {{Location mark |image=Taurus constellation map.svg|alt=|float=center|width=260 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=γ Tau |x=607|y=566 }} |caption=Location of γ Tauri (circled) }} {{Starbox observe | epoch = J2000 | ra = {{RA|04|19|47.6037}}<ref name="hipparcos"/> | dec = {{DEC|+15|37|39.512}}<ref name="hipparcos" /> | appmag_v = 3.654<ref name="SIMBAD" /> | constell = Taurus }} {{Starbox character | type = red clump<ref name=db2001/> | class = G8III<ref name="pasj60" /> | b-v = +0.99<ref name="yerkes53"/> | u-b = +0.84<ref name="yerkes53" /> | variable = }} {{Starbox astrometry | radial_v = {{nowrap|38.7 ± 0.9}}<ref name=rgcrv/> | prop_mo_ra = +115.29<ref name="hipparcos" /> | prop_mo_dec = -23.86<ref name="hipparcos" /> | parallax = 21.17 | p_error = 1.17 | parallax_footnote = <ref name="hipparcos" /> | absmag_v = 0.22<ref name="pasj60" /> }} {{Starbox detail | mass = {{nowrap|2.70 ± 0.13}}<ref name="aaa458" /> | radius = {{nowrap|13.4 ± 0.2}}<ref name="apj691" /> | luminosity = 85<ref name="pasj60" /> | temperature = {{nowrap|4,844 ± 47}}<ref name="apj691" /> | metal_fe = +0.11<ref name=aaa480_1_91/> | rotational_velocity = 4<ref name=coapa239_1/> | rotation = 253 days<ref name=aaa421_241/> | gravity = 2.58-2.61<ref name="apj691" /> | age_myr = 430–530<ref name="pasj60" /><ref name="aaa458" /> }} {{Starbox catalog | names = Prima Hyadum, Hyadum I,<ref name="hinckley" /> 54 Tauri, BD+15°612, FK5 159, HD 27371, HIP 20205, HR 1346, SAO 93868, GC 5226, WDS 04198+1538<ref name="SIMBAD"/> }} {{Starbox reference|Simbad=gam+Tau}} {{Starbox end}} '''Gamma Tauri''' ('''γ Tauri''', abbreviated '''Gamma Tau''', '''γ Tau''') is either a solitary, binary or double star (the Washington Double Star Catalog notes it as a "Dubious Double" or "Bogus Binary"<ref name="WDS">{{cite web | url=http://ad.usno.navy.mil/wds/ | title=Washington Double Star Catalog | publisher=United States Naval Observatory | access-date=2 January 2018 | archive-url=https://web.archive.org/web/20110214155533/http://ad.usno.navy.mil/wds/ | archive-date=14 February 2011 | url-status=dead }}</ref>) that marks the tip of the "V" in the constellation of Taurus. It is a member of, and located within about 2.5 parsecs of the center of, the Hyades star cluster, the nearest open cluster to the Sun. Based upon parallax measurements, Gamma Tauri is approximately 154 light-years from the Sun.
Considered as a pair of stars, the two components are designated Gamma Tauri A (officially named '''Prima Hyadum''' {{IPAc-en|,|p|r|ai|m|@|_|'|h|ai|@|d|@|m}}, the traditional name for the system)<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars | publisher=IAU.org | access-date=16 December 2017 | archive-date=10 March 2025 | archive-url=https://web.archive.org/web/20250310063743/https://www.iau.org/public/themes/naming_stars/ | url-status=dead }}</ref> and B.
== Nomenclature ==
''γ Tauri'' (Latinised to ''Gamma Tauri'') is the system's Bayer designation. The designations of the two potential components as ''Gamma Tauri A'' and ''B'' derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).<ref name="planetnaming">{{cite arXiv |title=On the naming convention used for multiple star systems and extrasolar planets |date=2010 |eprint=1012.0707 |class=astro-ph.SR |last1= Hessman |first1=F. V. |last2= Dhillon |first2=V. S. |last3= Winget |first3=D. E. |last4= Schreiber |first4=M. R. |last5= Horne |first5=K. |last6= Marsh |first6=T. R. |last7= Guenther |first7=E. |last8= Schwope |first8=A. |last9= Heber |first9=U. }}</ref>
Gamma Tauri bore the traditional name ''Hyadum I'',<ref name="hinckley">{{cite book | last=Allen | first=R. H. | date=1963 | author-link=Richard Hinckley Allen | title=Star Names: Their Lore and Meaning | edition=Reprint | publisher=Dover Publications Inc. | location=New York, NY | isbn=0-486-21079-0 | page=[https://archive.org/details/starnamestheirlo00alle/page/390 390] }}</ref> which is Latin for "First of the Hyades". In 2016, the IAU organized a Working Group on Star Names (WGSN)<ref name="WGSN">{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN) | access-date=22 May 2016 | archive-date=30 March 2019 | archive-url=https://web.archive.org/web/20190330194042/https://www.iau.org/science/scientific_bodies/working_groups/280/ | url-status=dead }}</ref> to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.<ref name="TriRpt18">{{cite web | url=https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf | page=5 | title=WG Triennial Report (2015-2018) - Star Names | access-date=2018-07-14 | archive-date=2019-08-23 | archive-url=https://web.archive.org/web/20190823174756/https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf | url-status=dead }}</ref> It approved the name ''Prima Hyadum'' for the component Gamma Tauri A on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN"/>
In Chinese, {{lang|zh|畢宿}} ({{lang|zh-Latn|Bì Xiù}}), meaning ''Net'', refers to an asterism consisting of Gamma Tauri, Epsilon Tauri, Delta³ Tauri, Delta¹ Tauri, Alpha Tauri (Aldebaran), 71 Tauri and Lambda Tauri.<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 γ Tauri itself is {{lang|zh|畢宿四}} ({{lang|zh-Latn|Bì Xiù sì}}), "the Fourth Star of Net".<ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ala_alz.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive|url=https://web.archive.org/web/20081025110153/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ala_alz.htm |date=2008-10-25 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref>
== Properties ==
Gamma Tauri presents as a spectral class G8 or K0<ref name="SIMBAD" /><ref name="pasj60" /> giant star with an apparent magnitude of +3.65. This star has passed through the main sequence phase is now a red clump giant, meaning it is using nuclear fusion of helium at its core to provide energy.<ref name=db2001>{{cite journal | author1=de Bruijne, J. H. J. |author2=Hoogerwerf, R. |author3=de Zeeuw, P. T. | title=A Hipparcos study of the Hyades open cluster. Improved colour-absolute magnitude and Hertzsprung-Russell diagrams | journal=Astronomy and Astrophysics | volume=367 | issue=1 | pages=111–147 |date=February 2001 | doi=10.1051/0004-6361:20000410 | bibcode=2001A&A...367..111D|arxiv = astro-ph/0011565 |s2cid=55224801 }}</ref> Age estimates for Gamma Tauri range from 430 million<ref name="pasj60">{{cite journal | author1=Takeda, Yoichi |author2=Sato, Bun'ei |author3=Murata, Daisuke | title=Stellar Parameters and Elemental Abundances of Late-G Giants | journal=Publications of the Astronomical Society of Japan |date=August 2008 | volume=60 | issue=4 | pages=781–802 | bibcode=2008PASJ...60..781T | arxiv = 0805.2434 | doi=10.1093/pasj/60.4.781 |s2cid=16258166 }}</ref> to 530 million years.<ref name="aaa458">{{cite journal | author=da Silva, L. | title=Basic physical parameters of a selected sample of evolved stars | journal=Astronomy and Astrophysics | volume=458 | issue=2 |date=November 2006 | pages=609–623 | doi=10.1051/0004-6361:20065105 |display-authors=etal | bibcode=2006A&A...458..609D|arxiv = astro-ph/0608160 | s2cid=9341088 }}</ref> By comparison, the age of the Hyades cluster is about 625 million years with an error margin of 50 million years.<ref name="aaa458" />
The angular diameter of this star has been measured using the CHARA array to 2% accuracy. After correcting for limb darkening, this gives the stellar radius as 13.4 times the radius of the Sun.<ref name="apj691">{{cite journal | author=Boyajian, Tabetha S. |display-authors=etal | title=Angular Diameters of the Hyades Giants Measured with the CHARA Array |date=February 2009 | journal=The Astrophysical Journal | volume=691 | issue=2 | pages=1243–1247 | doi=10.1088/0004-637X/691/2/1243 | bibcode=2009ApJ...691.1243B|arxiv = 0810.2238 |s2cid=17092177 }}</ref> The star is radiating about 85 times the luminosity of the Sun<ref name="pasj60" /> and has 2.7 times the Sun's mass.<ref name="aaa458" /> With its large size and low projected rotational velocity of {{nowrap|4 km s<sup>−1</sup>}},<ref name=coapa239_1/> it takes about 253 days to complete a rotation.<ref name=aaa421_241/>
==References== {{reflist|30em|refs=
<ref name="hipparcos">{{citation | display-authors=1 | last1=Perryman | first1=M. A. C. | last2=Lindegren | first2=L. | last3=Kovalevsky | first3=J. | last4=Hoeg | first4=E. | last5=Bastian | first5=U. | last6=Bernacca | first6=P. L. | last7=Crézé | first7=M. | last8=Donati | first8=F. | last9=Grenon | first9=M. | title=The Hipparcos Catalogue | journal=Astronomy & Astrophysics | date=1997 | volume=323 | pages=L49–L52 | bibcode=1997A&A...323L..49P }}</ref>
<ref name="yerkes53">{{cite journal | last1=Johnson | first1=H. L. | last2=Morgan | first2=W. W. | title=Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas | journal=Astrophysical Journal | date=1953 | volume=117 | pages=313–352 | bibcode=1953ApJ...117..313J | doi=10.1086/145697 }}</ref>
<ref name=rgcrv>{{cite conference | last=Evans | first=D. S. | date=June 20–24, 1966 | editor1=Batten, Alan Henry |editor2=Heard, John Frederick | title=The Revision of the General Catalogue of Radial Velocities | book-title=Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 | location=University of Toronto | publisher=International Astronomical Union | bibcode=1967IAUS...30...57E }}</ref>
<ref name=aaa480_1_91>{{cite journal |author1=Soubiran, C. |author2=Bienaymé, O. |author3=Mishenina, T. V. |author4=Kovtyukh, V. V. | title=Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants | journal=Astronomy and Astrophysics | volume=480 | issue=1|date=March 2008 | pages=91–101 | doi=10.1051/0004-6361:20078788 | bibcode=2008A&A...480...91S |arxiv = 0712.1370 |s2cid=16602121 }}</ref>
<ref name=coapa239_1>{{cite journal |author1=Bernacca, P. L. |author2=Perinotto, M. | title=A catalogue of stellar rotational velocities | journal=Contributi Osservatorio Astronomico di Padova in Asiago | volume=239 | issue=1 | date=1970 |page=1 | bibcode=1970CoAsi.239....1B }}</ref>
<ref name=aaa421_241>{{citation | display-authors=1 | last1=Setiawan | first1=J. | last2=Pasquini | first2=L. | last3=da Silva | first3=L. | last4=Hatzes | first4=A. P. | last5=von der Lühe | first5=O. | last6=Girardi | first6=L. | last7=de Medeiros | first7=J. R. | last8=Guenther | first8=E. | title=Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch | journal=Astronomy and Astrophysics | volume=421 | pages=241–254 |date=July 2004 | doi=10.1051/0004-6361:20041042-1 | bibcode=2004A&A...421..241S | doi-access=free }}</ref>
<ref name="SIMBAD">{{cite web | title=NSV 1553 - Variable Star | publisher=Centre de Données astronomiques de Strasbourg | work=SIMBAD | url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NSV+1553 | access-date=2009-09-22 }}</ref>
}}
{{Stars of Taurus}}
{{Authority control}}
Category:G-type giants Category:Horizontal-branch stars Category:Hyades (star cluster) Category:Taurus (constellation) Prima Hyadum Tauri, Gamma Category:Durchmusterung objects Tauri, 054 027371 020205 1346 Category:Population I stars