{{short description|Star in the constellation Taurus}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Taurus constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=8|mark_link=71 Tauri |x=565|y=568 }} | caption = Location of 71 Tauri (circled in red) }} {{Starbox observe | epoch = J2000.0 | constell = Taurus | ra = {{RA|04|26|20.77082}}<ref name=GaiaDR3/> | dec = {{DEC|+15|37|05.8841}}<ref name=GaiaDR3/> | appmag_v = +4.48<ref name="MERMILLIOD"/> }} {{Starbox character | type = main sequence<ref name=GaiaDR3/> | class = F0&nbsp;V<ref name=Mullan2000/> | b-v = +0.25<ref name="MERMILLIOD"/> | u-b = +0.13<ref name="MERMILLIOD"/> | variable = δ Sct<ref name=Samus2017/> }} {{Starbox astrometry | radial_v = +38.3<ref name=rgcrv/> | prop_mo_ra = +87.435<ref name=GaiaDR3/> | prop_mo_dec = −20.978<ref name=GaiaDR3/> | parallax = 21.3957 | p_error = 0.2511 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = 1.10<ref name=aaa361_614/> }} {{Starbox detail | mass = 1.94<ref name=aaa361_614/> | radius = 3.34<ref name=Mullan2000/> | luminosity = | gravity = 3.73<ref name=David2015/> | temperature = 7,543<ref name=Mullan2000/> | metal_fe = | rotation = 14.2<ref name=aaa361_614/>&nbsp;d | rotational_velocity = 192<ref name=aaa361_614/> | age_myr = 966<ref name=David2015/> }} {{Starbox catalog | names = {{odlist | F=71 Tau | V=V777 Tau | BD=+15°625 | HD=28052 | HIP=20713 | HR=1394 | SAO=93932 | GC=5375 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad=71+Tau }} {{Starbox end}}

'''71 Tauri''' is a suspected triple star<ref name=Eggleton2008/> system in the zodiac constellation Taurus, located 152&nbsp;light years from the Sun.<ref name=GaiaDR3/> It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of +4.48.<ref name="MERMILLIOD"/> The star is moving further away from the Earth with a heliocentric radial velocity of +38&nbsp;km/s.<ref name=rgcrv/> It is a member of the Hyades open cluster.<ref name=Simon2000/>

[[File:V777TauLightCurve.png|thumb|left|250px|A light curve for V777 Tauri, plotted from ''TESS'' data<ref name=MAST/>]]

The primary component is an F-type main-sequence star with a stellar classification of F0&nbsp;V.<ref name=Mullan2000/> In 1979, Stephen Horan discovered that 71 Tauri is a variable star.<ref name="AJ1979"/> It was given its variable star designation, V777 Tauri, in 1981.<ref name="IBVS1981"/> It is a Delta Scuti variable with an amplitude of 0.02 in magnitude and a frequency of 0.16&nbsp;d<sup>−1</sup>.<ref name=Samus2017/> This star has about 1.94<ref name=aaa361_614/> times the mass of the Sun and 3.34<ref name=Mullan2000/> times the Sun's radius. It has a projected rotational velocity of 192&nbsp;km s<sup>−1</sup>, for an estimated rotation period of 14.2 days.<ref name=aaa361_614/> Extreme ultraviolet flares have been observed coming from this star's hot corona,<ref name=Mullan2000/> and it is the second brightest X-ray source in the Hyades.<ref name=Simon2000/> {{clear left}} ==References== <references> <ref name=GaiaDR3>{{cite DR3|3312759303913978624}}</ref>

<ref name=MAST>{{cite web | title=MAST: Barbara A. Mikulski Archive for Space Telescopes | url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html | publisher=Space Telescope Science Institute |access-date=8 December 2021}}</ref>

<ref name="AJ1979">{{cite journal | last1=Horan | first1=S. | title=A photometric survey of the Hyades for delta Scuti variables | journal=Astronomical Journal | date=November 1979 | volume=84 | pages=1770-1774 | doi=10.1086/112607 | bibcode=1979AJ.....84.1770H }}</ref>

<ref name="IBVS1981">{{cite journal | last1=Kholopov | first1=P. N. | last2=Samus | first2=N. N. | last3=Kukarkina | first3=N. P. | last4=Medvedeva | first4=G. I. | last5=Perova | first5=N. B. | title=65th Name-List of Variable Stars | journal=Information Bulletin on Variable Stars | date=February 1981 | volume=1921 | pages=1-21 | bibcode=1981IBVS.1921....1K | url=https://ibvs.konkoly.hu/pub/ibvs/1901/1921.pdf | access-date=3 September 2025}}</ref>

<ref name=aaa361_614>{{citation | last1=Pizzolato | first1=N. | last2=Maggio | first2=A. | last3=Sciortino | first3=S. | title=Evolution of X-ray activity of 1-3 M<sub>sun</sub> late-type stars in early post-main-sequence phases | journal=Astronomy and Astrophysics | volume=361 | pages=614–628 | date=September 2000 | bibcode=2000A&A...361..614P | postscript=. }}</ref>

<ref name=Mullan2000>{{citation | title=Extreme-Ultraviolet Flares in an F2 Star | last1=Mullan | first1=D. J. | last2=Mathioudakis | first2=M. | journal=The Astrophysical Journal | volume=544 | issue=1 | pages=475–480 | date=November 2000 | doi=10.1086/317202 | bibcode=2000ApJ...544..475M | postscript=. | doi-access=free }}</ref>

<ref name=SIMBAD>{{citation | title=71 Tau -- Variable Star of delta Sct type | work=SIMBAD Astronomical Database | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=71+tauri | access-date=2007-01-25 }}</ref>

<ref name=rgcrv>{{citation | last=Evans | first=D. S. | date=June 20–24, 1966 | editor1-last=Batten | editor1-first=Alan Henry | editor2-last=Heard | editor2-first=John Frederick | title=The Revision of the General Catalogue of Radial Velocities | work=Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 | volume=30 | page=57 | location=University of Toronto | publisher=International Astronomical Union | bibcode=1967IAUS...30...57E | postscript=. }}</ref>

<ref name="MERMILLIOD">{{citation | last1=Mermilliod | first1=J.-C. | title=Compilation of Eggen's UBV data, transformed to UBV (unpublished) | journal=Catalogue of Eggen's UBV Data. SIMBAD | date=1986 | bibcode=1986EgUBV........0M | postscript=. }}</ref>

<ref name=Samus2017>{{citation | display-authors=1 | last1=Samus | first1=N. N. | last2=Kazarovets | first2=E. V. | last3=Durlevich | first3=O. V. | last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N. | title=General Catalogue of Variable Stars | version=5.1 | journal=Astronomy Reports | year=2017 | volume=61 | issue=1 | pages=80–88 | doi=10.1134/S1063772917010085 | bibcode=2017ARep...61...80S | s2cid=125853869 | postscript=. }}</ref>

<ref name=David2015>{{citation | last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A. | title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets | journal=The Astrophysical Journal | volume=804 | issue=2 | pages=146 | year=2015 | bibcode=2015ApJ...804..146D | doi=10.1088/0004-637X/804/2/146 | arxiv=1501.03154 | s2cid=33401607 | postscript=. }}</ref>

<ref name=Eggleton2008>{{citation | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869–879 | date=September 2008 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | postscript=. | bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 }}</ref>

<ref name=Simon2000>{{citation | title=71 Tauri: Hyades Enigma Resolved? | last1=Simon | first1=Theodore | last2=Ayres | first2=Thomas R. | journal=The Astrophysical Journal | postscript=. | volume=539 | issue=1 | pages=325–330 | date=August 2000 | doi=10.1086/309228 | bibcode=2000ApJ...539..325S | doi-access=free }}</ref> </references>

{{Stars of Taurus}}

Category:F-type main-sequence stars Category:Delta Scuti variables Category:Triple star systems Category:Taurus (constellation) Tauri, V777 BD+15 0625 Tauri, 071 028052 020713 1394 Category:Hyades (star cluster)