# Pi Tauri

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Pi_Tauri
> Markdown URL: https://mediated.wiki/source/Pi_Tauri.md
> Source: https://en.wikipedia.org/wiki/Pi_Tauri
> Source revision: 1345573317
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

{{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=10|mark_link=π Tauri
|x=560|y=592
}}
| caption = Location of π Tauri (circled in red)
}}
{{Starbox observe
 | epoch = [J2000.0](/source/J2000.0)
 | equinox = [J2000.0](/source/J2000.0) ([ICRS](/source/International_Celestial_Reference_System))
 | constell = [Taurus](/source/Taurus_(constellation))<ref name=xhip/>
 | ra = {{RA|04|26|36.37093}}<ref name=vanLeeuwen2007/>
 | dec = {{DEC|+14|42|49.6126}}<ref name=vanLeeuwen2007/>
 | appmag_v = +4.69<ref name=Argue1966/>
}}
{{Starbox character
 | type = [horizontal branch](/source/horizontal_branch)<ref name=stock2018/>
 | class = {{nowrap|G7 IIIa Fe-1}}<ref name=Keenan1989/>
 | b-v = +0.98<ref name=Argue1966/>
 | u-b = +0.72<ref name=Argue1966/>
 | variable = 
}}
{{Starbox astrometry
 | radial_v = {{Val|+31.4|0.3}}<ref name=deBruijne2012/>
 | prop_mo_ra = −9.52<ref name=vanLeeuwen2007/>
 | prop_mo_dec = −31.44<ref name=vanLeeuwen2007/>
 | parallax = 7.83
 | p_error = 0.22
 | parallax_footnote = <ref name=vanLeeuwen2007/>
 | absmag_v = −0.84<ref name=xhip/>
}}
{{Starbox detail
 | mass = 4.4<ref name=vanbelle2021/>
 | radius = 22<ref name=vanbelle2021/>
 | luminosity = 244<ref name=yu2023/>
 | temperature 5,006<ref name=das2025/>
 | gravity = 2.39<ref name=das2025/>
 | metal_fe = −0.08<ref name=das2025/>
 | rotational_velocity = 7.1<ref name=das2025/>
 | age_myr = 554<ref name=ting2019/>
}}
{{Starbox catalog
 | names = {{odlist | B=π&nbsp;Tau | F=73&nbsp;Tau | BD=+14°697 | HD=28100 | HIP=20732 | HR=1396 | SAO=93935 }}<ref name=SIMBAD/>
}}
{{Starbox reference
 | Simbad = pi.+Tau
}}
{{Starbox end}}
'''Pi Tauri''' (π Tauri) is a solitary,<ref name=Eggleton2008/> yellow-hued [star](/source/star) in the [zodiac](/source/zodiac) [constellation](/source/constellation) of [Taurus](/source/Taurus_(constellation)). With an [apparent visual magnitude](/source/apparent_visual_magnitude) of +4.69,<ref name=Argue1966/> it is bright enough to be visible to the naked eye. Although it appears to lie among the stars of the [Hyades cluster](/source/Hyades_(star_cluster)), it is not itself a member, being three times farther from Earth than the cluster. The distance to this star, as determined using an annual [parallax](/source/parallax) shift of 7.83&nbsp;[mas](/source/milliarcsecond) as seen from the Earth,<ref name=vanLeeuwen2007/> is around 420&nbsp;[light year](/source/light_year)s. At that range, the visual magnitude of the star is diminished by [extinction](/source/extinction_(astronomy)) of 0.24 magnitudes due to [interstellar dust](/source/interstellar_dust).<ref name=Takeda2008/>

This is an [evolved](/source/stellar_evolution) [G-type](/source/G-type_giant) [giant star](/source/giant_star) with a [stellar classification](/source/stellar_classification) of {{nowrap|G7 IIIa Fe-1}},<ref name=Keenan1989/> where the suffix notation indicates an underabundance of iron in the [spectrum](/source/stellar_spectrum). The measured [angular diameter](/source/angular_diameter) is {{Val|1.55|0.06|u=mas}}.<ref name=Richichi2005/> At the estimated distance of Pi Tauri, this yields a physical size of about 22 times the [radius of the Sun](/source/Solar_radius).<ref name=vanbelle2021/> It possesses 4.4 times the [mass of the Sun](/source/mass_of_the_Sun)<ref name=vanbelle2021/> and is radiating 244 times the [Sun's luminosity](/source/Sun's_luminosity)<ref name=yu2023/> at an [effective temperature](/source/effective_temperature) of {{val|5,006|ul=K}}.<ref name=das2025/>

==References==
<references>
<ref name=vanLeeuwen2007>{{citation
 | title=Validation of the new Hipparcos reduction
 | last1=van Leeuwen | first1=F.
 | journal=Astronomy and Astrophysics
 | volume=474 | issue=2 | pages=653–664 | date=2007
 | arxiv=0708.1752 | bibcode=2007A&A...474..653V
 | doi=10.1051/0004-6361:20078357 | s2cid=18759600 | postscript=. }}</ref>

<ref name=Richichi2005>{{citation
 | display-authors=1 | last1=Richichi | first1=A.
 | last2=Percheron | first2=I. | last3=Khristoforova | first3=M.
 | title=CHARM2: An updated Catalog of High Angular Resolution Measurements
 | journal=Astronomy and Astrophysics | postscript=.
 | volume=431 | issue=2 | pages=773–777 | date=February 2005
 | doi=10.1051/0004-6361:20042039 | bibcode=2005A&A...431..773R | doi-access=free }}</ref>

<ref name=Takeda2008>{{citation
 | display-authors=1 | last1=Takeda | first1=Yoichi
 | last2=Sato | first2=Bun'ei | last3=Murata | first3=Daisuke
 | title=Stellar Parameters and Elemental Abundances of Late-G Giants
 | journal=Publications of the Astronomical Society of Japan
 | volume=60 | issue=4 | pages=781–802 | date=August 2008
 | bibcode=2008PASJ...60..781T | doi=10.1093/pasj/60.4.781
 | arxiv = 0805.2434 | 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
 | bibcode=2008MNRAS.389..869E | doi=10.1111/j.1365-2966.2008.13596.x
 | doi-access=free | arxiv=0806.2878 | s2cid=14878976 | postscript=. }}</ref>

<ref name=deBruijne2012>{{citation
 | last1=de Bruijne | first1=J. H. J. | last2=Eilers | first2=A.-C. 
 | title=Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project 
 | journal=Astronomy & Astrophysics
 | volume=546 | id=A61 | pages=14 | date=October 2012
 | doi=10.1051/0004-6361/201219219 | bibcode=2012A&A...546A..61D 
 | arxiv=1208.3048 | s2cid=59451347 | postscript=. }}</ref>

<ref name=Keenan1989>{{citation
 | last1=Keenan | first1=Philip C. | last2=McNeil | first2=Raymond C.
 | title=The Perkins catalog of revised MK types for the cooler stars
 | journal=Astrophysical Journal Supplement Series
 | volume=71 | pages=245 | year=1989 | postscript=.
 | bibcode=1989ApJS...71..245K | doi=10.1086/191373 }}</ref>

<ref name=Argue1966>{{citation
 | last1=Argue | first1=A. N. | postscript=.
 | title=UBV photometry of 550 F, G and K type stars
 | journal=[Monthly Notices of the Royal Astronomical Society](/source/Monthly_Notices_of_the_Royal_Astronomical_Society)
 | volume=133 | pages=475–493 | year=1966
 | issue=4 | bibcode=1966MNRAS.133..475A | doi=10.1093/mnras/133.4.475| doi-access=free}}</ref>

<ref name=SIMBAD>{{cite simbad
 | title=pi Tau | access-date=2017-06-30 }}</ref>

<ref name=stock2018>{{cite journal |last1=Stock |first1=Stephan |last2=Reffert |first2=Sabine |last3=Quirrenbach |first3=Andreas |title=Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search |journal=Astronomy and Astrophysics |date=2018 |volume=616 |pages=A33 |doi=10.1051/0004-6361/201833111 |arxiv=1805.04094 |bibcode=2018A&A...616A..33S }}</ref>

<ref name=ting2019>{{cite journal |last1=Ting |first1=Yuan-Sen |last2=Rix |first2=Hans-Walter |title=The Vertical Motion History of Disk Stars throughout the Galaxy |journal=The Astrophysical Journal |date=2019 |volume=878 |issue=1 |page=21 |doi=10.3847/1538-4357/ab1ea5 |doi-access=free |arxiv=1808.03278 |bibcode=2019ApJ...878...21T }}</ref>

<ref name=vanbelle2021>{{cite journal |last1=Van Belle |first1=Gerard T. |last2=von Braun |first2=Kaspar |last3=Ciardi |first3=David R. |last4=Pilyavsky |first4=Genady |last5=Buckingham |first5=Ryan S. |last6=Boden |first6=Andrew F. |last7=Clark |first7=Catherine A. |last8=Hartman |first8=Zachary |last9=Van Belle |first9=Gerald |last10=Bucknew |first10=William |last11=Cole |first11=Gary |title=Direct Measurements of Giant Star Effective Temperatures and Linear Radii: Calibration against Spectral Types and V - K Color |journal=The Astrophysical Journal |date=2021 |volume=922 |issue=2 |page=163 |doi=10.3847/1538-4357/ac1687 |doi-access=free |arxiv=2107.09205 |bibcode=2021ApJ...922..163V }}</ref>

<ref name=yu2023>{{cite journal |last1=Yu |first1=Jie |last2=Khanna |first2=Shourya |last3=Themessl |first3=Nathalie |last4=Hekker |first4=Saskia |last5=Dréau |first5=Guillaume |last6=Gizon |first6=Laurent |last7=Bi |first7=Shaolan |title=Revised Extinctions and Radii for 1.5 Million Stars Observed by APOGEE, GALAH, and RAVE |journal=The Astrophysical Journal Supplement Series |date=2023 |volume=264 |issue=2 |page=41 |doi=10.3847/1538-4365/acabc8 |doi-access=free |arxiv=2206.00046 |bibcode=2023ApJS..264...41Y }}</ref>

<ref name=das2025>{{cite journal |last1=Das |first1=Pradosh Barun |last2=Zucker |first2=Daniel B. |last3=De Silva |first3=Gayandhi M. |last4=Borsato |first4=Nicholas W. |last5=Mura-Guzmán |first5=Aldo |last6=Buder |first6=Sven |last7=Ness |first7=Melissa |last8=Nordlander |first8=Thomas |last9=Casey |first9=Andrew R. |last10=Martell |first10=Sarah L. |last11=Bland-Hawthorn |first11=Joss |last12=De Grijs |first12=Richard |last13=Freeman |first13=Ken C. |last14=Kos |first14=Janez |last15=Stello |first15=Dennis |last16=Lewis |first16=Geraint F. |last17=Hayden |first17=Michael R. |last18=Sharma |first18=Sanjib |title=The GALAH Survey: Stellar parameters and abundances for 800 000 Gaia RVS spectra using GALAH DR4 and the Cannon |journal=Monthly Notices of the Royal Astronomical Society |date=2025 |volume=538 |issue=2 |page=605 |doi=10.1093/mnras/staf169 |doi-access=free |arxiv=2410.12272 |bibcode=2025MNRAS.538..605D }}</ref>

<ref name=xhip>{{cite XHIP|20732}}</ref>

</references>

{{Stars of Taurus|state=collapsed}}

Category:G-type giants
Tauri, Pi
Category:Taurus (constellation)
BD+14 0697
Tauri, 073
028100
020732
1396
Category:Horizontal-branch stars

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Adapted from the Wikipedia article [Pi Tauri](https://en.wikipedia.org/wiki/Pi_Tauri) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Pi_Tauri?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.