Pi Tauri
{{Short description|Star in the constellation Taurus}}
{{Starbox begin
| name = Pi Tauri
}}
{{Starbox observe
| epoch = J2000.0
| constell = Taurus
| dec = {{DEC|+14|42|49.6126}}
}}
{{Starbox character
| class = {{nowrap|G7 IIIa Fe-1}}
| variable =
}}
{{Starbox astrometry
| radial_v = {{Val|+31.4|0.3}}
| parallax = 7.83
| p_error = 0.22
}}
{{Starbox detail
| source =
| rotational_velocity =
}}
{{Starbox catalog
| names = {{odlist | B=π Tau | F=73 Tau | BD=+14°697 | HD=28100 | HIP=20732 | HR=1396 | SAO=93935 }}
}}
{{Starbox reference
| Simbad = pi.+Tau
}}
{{Starbox end}}
Pi Tauri (π Tauri) is a solitary, yellow-hued star in the zodiac constellation of Taurus. With an apparent visual magnitude of +4.69, it is bright enough to be visible to the naked eye. Although it appears to lie among the stars of the Hyades 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 shift of 7.83 mas as seen from the Earth, is around 420 light years. At that range, the visual magnitude of the star is diminished by an extinction factor of 0.24 due to interstellar dust.
This is an evolved G-type giant star with a stellar classification of {{nowrap|G7 IIIa Fe-1}}, where the suffix notation indicates an underabundance of iron in the spectrum. The measured angular diameter is {{Val|1.55|0.06|u=mas}}. At the estimated distance of Pi Tauri, this yields a physical size of about 21 times the radius of the Sun. It possesses nearly four times the mass of the Sun and is radiating 229 times the Sun's luminosity at an effective temperature of 5,086 K.
References
{{reflist|refs=
| 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=. }}
| 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 }}
| first1=Kenneth R. | last1=Lang
| title=Astrophysical formulae | volume=1
| series=Astronomy and astrophysics library
| edition=3rd | publisher=Birkhäuser
| date=2006 | isbn=3-540-29692-1 | postscript=.
| url=https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41
}} The radius (R*) is given by:
:
& = \frac{(127.7\cdot 1.55\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
& \approx 42.6\cdot R_{\bigodot}
\end{align}
| 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=.}}
| 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=. }}
| display-authors=1 | last1=McDonald | first1=I.
| last2=Zijlstra | first2=A. A. | last3=Boyer | first3=M. L.
| title=Fundamental Parameters and Infrared Excesses of Hipparcos Stars
| journal=Monthly Notices of the Royal Astronomical Society
| volume=427 | issue=1 | pages=343–57 | date=2012
| bibcode=2012MNRAS.427..343M | arxiv=1208.2037
| doi=10.1111/j.1365-2966.2012.21873.x | doi-access=free | s2cid=118665352 | postscript=. }}
| 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=. }}
| 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 }}
| 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
| volume=133 | pages=475–493 | year=1966
| issue=4 | bibcode=1966MNRAS.133..475A | doi=10.1093/mnras/133.4.475| doi-access=free}}
| title=pi Tau | access-date=2017-06-30 }}
}}
{{Stars of Taurus|state=collapsed}}
{{DEFAULTSORT:Pi Tauri}}
Category:Taurus (constellation)