{{Short description|Star in the constellation Taurus}} {{Starbox begin | name = Phi Tauri }} {{Starbox image | image = {{Location mark | image=Taurus IAU.svg | alt= | float=center | width=250 | label= | position=right | mark=Red circle.svg | mark_width=10 | mark_link=α Tau | x=601 | y=231 }} | caption=Location of φ Tauri (circled) }} {{Starbox observe | epoch = J2000.0 | equinox = J2000.0 (ICRS) | constell = Taurus | ra = {{RA|04|20|21.21580}}<ref name=vanLeeuwen2007/> | dec = {{DEC|+27|21|02.7009}}<ref name=vanLeeuwen2007/> | appmag_v = +4.957<ref name=Luck2015/> }} {{Starbox character | class = K1 III<ref name=Luck2015/> | b-v = 1.154<ref name=Luck2015/> | u-b = | variable = }} {{Starbox astrometry | radial_v = 1.27<ref name=Luck2015/> | prop_mo_ra = −28.90<ref name=vanLeeuwen2007/> | prop_mo_dec = −78.28<ref name=vanLeeuwen2007/> | parallax = 10.16 | p_error = 0.26 | parallax_footnote = <ref name=vanLeeuwen2007/> | absmag_v = −0.15<ref name=Luck2007/> }} {{Starbox detail | source = <ref name=Reffert2015/> | mass = {{Val|1.36|0.19}} | radius = {{Val|19.04|0.56}} | luminosity = {{Val|131.0|6.8}} | temperature = {{Val|4479|30|fmt=commas}} | gravity = {{Val|2.02|0.08}} | metal_fe = {{Val|−0.32|0.10}} | rotational_velocity = 1.0<ref name=DeMedeiros2000/> | age_gyr = {{Val|4.74|2.56}} }} {{Starbox catalog | names = {{odlist | B=φ Tau | F=52 Tauri | BD=+27°655 | HD=27382 | HIP=20250 | HR=1348 | SAO=76558 | ADS=3137 | WDS=J04204+2721A }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = phi+Tau }} {{Starbox end}} '''Phi Tauri''' (φ Tauri) is a solitary,<ref name=Eggleton2008/> orange-hued star in the zodiac constellation of Taurus. It has an apparent visual magnitude of +4.96,<ref name=Luck2015/> which indicates the star is faintly visible to the naked eye. Based upon an annual parallax shift of 10.16 mas as seen from Earth,<ref name=vanLeeuwen2007/> it is located roughly 321 light years distant from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.27 due to interstellar dust.<ref name=Famaey2005/>
This is an evolved, K-type giant star with a stellar classification of K1 III,<ref name=Luck2015/> currently (97% probability) on the red giant branch. It has an estimated 1.36 times the mass of the Sun and has expanded to 19 times the Sun's radius. At the age of roughly five billion years, it is radiating 131 times the Sun's luminosity from its inflated photosphere at an effective temperature of 4,479 K.<ref name=Reffert2015/>
Phi Tauri has a magnitude 7.51 visual companion located at an angular separation of 48.80 arc seconds along a position angle of 258°, as of 2015. The pair form a yellow and blue double that is visible in small telescopes.<ref name=Privett2013/> A fainter, magnitude 12.27 companion lies at a separation of 118.10 arc seconds along a position angle of 25°, as of 2001.<ref name=WDSC2014/>
==Naming== *With κ<sup>1</sup>, κ<sup>2</sup>, υ and χ, it composed the Arabic were the Arabs' '''Al Kalbain''', the Two Dogs.<ref name="allen1899"/> According to the catalogue of stars in the ''Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars'', ''Al Kalbain'' were the title for five stars : this star (φ) as ''Alkalbain I'', χ as ''Alkalbain II'', κ<sup>1</sup> as ''Alkalbain III'', κ<sup>2</sup> as ''Alkalbain IV'' and υ as ''Alkalbain V''.<ref name=rhoads1971/> *In Chinese, {{lang|zh|礪石}} ({{lang|zh-Latn|Lì Dàn}}), meaning ''Whetstone'', refers to an asterism consisting of φ Tauri, ψ Tauri, 44 Tauri and χ Tauri. Consequently, the Chinese name for φ Tauri itself is {{lang|zh|礪石四}} ({{lang|zh-Latn|Lì Dàn sì}}, {{langx|en|the Fourth Star of Whetstone}}.).<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0605/ap060522.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 22 日] {{Webarchive|url=https://web.archive.org/web/20110928011211/http://aeea.nmns.edu.tw/2006/0605/ap060522.html |date=2011-09-28 }}</ref>
==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=Luck2007>{{citation | last1=Luck | first1=R. Earle | last2=Heiter | first2=Ulrike | title=Giants in the Local Region | postscript=. | journal=The Astronomical Journal | volume=133 | issue=6 | pages=2464–2486 | date=June 2007 | doi=10.1086/513194 | bibcode=2007AJ....133.2464L | doi-access=free }}</ref>
<ref name=Privett2013>{{citation | title=The Constellation Observing Atlas | series=The Patrick Moore Practical Astronomy Series | first1=Grant | last1=Privett | first2=Kevin | last2=Jones | publisher=Springer Science & Business Media | year=2013 | isbn=978-1461476481 | page=187 | bibcode=2013coa..book.....P | postscript=. | url=https://books.google.com/books?id=uN69BAAAQBAJ&pg=PA187 }}</ref>
<ref name=Reffert2015>{{citation | display-authors=1 | last1=Reffert | first1=Sabine | last2=Bergmann | first2=Christoph | last3=Quirrenbach | first3=Andreas | last4=Trifonov | first4=Trifon | last5=Künstler | first5=Andreas | title=Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity | journal=Astronomy & Astrophysics | volume=574 | pages=A116 | year=2015 | doi=10.1051/0004-6361/201322360 | bibcode=2015A&A...574A.116R | arxiv=1412.4634 | postscript=. | hdl=10722/215277| s2cid=59334290 }}</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=DeMedeiros2000>{{citation | display-authors=1 | last1=De Medeiros | first1=J. R. | last2=do Nascimento | first2=J. D. Jr. | last3=Sankarankutty | first3=S. | last4=Costa | first4=J. M. | last5=Maia | first5=M. R. G. | title=Rotation and lithium in single giant stars | journal=Astronomy and Astrophysics | postscript=. | volume=363 | pages=239–243 | date=November 2000 | bibcode=2000A&A...363..239D | arxiv=astro-ph/0010273 }}</ref>
<ref name=Famaey2005>{{citation | display-authors=1 | last1=Famaey | first1=B. | last2=Jorissen | first2=A. | last3=Luri | first3=X. | last4=Mayor | first4=M. | last5=Udry | first5=S. | last6=Dejonghe | first6=H. | last7=Turon | first7=C. | title=Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters | journal=Astronomy and Astrophysics | volume=430 | issue=1 | pages=165–186 | date=January 2005 | doi=10.1051/0004-6361:20041272 | bibcode=2005A&A...430..165F | arxiv=astro-ph/0409579 | s2cid=17804304 | postscript=. }}</ref>
<ref name=Luck2015>{{citation | title=Abundances in the Local Region. I. G and K Giants | last1=Luck | first1=R. Earle | journal=The Astronomical Journal | volume=150 | issue=3 | id=88 | pages=23 | date=September 2015 | doi=10.1088/0004-6256/150/3/88 | bibcode=2015AJ....150...88L | arxiv=1507.01466 | s2cid=118505114 | postscript=. }}</ref>
<ref name=WDSC2014>{{citation | display-authors=1 | last1=Mason | first1=B. D. | last2=Wycoff | first2=G. L. | last3=Hartkopf | first3=W. I. | last4=Douglass | first4=G. G. | last5=Worley | first5=C. E. | title=The Washington Visual Double Star Catalog | journal=The Astronomical Journal | year=2014 | volume=122 | issue=6 | page=3466 | bibcode=2001AJ....122.3466M | url=http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/wds | access-date=2015-07-22 | doi = 10.1086/323920 | doi-access=free }}</ref>
<ref name=SIMBAD>{{cite simbad | title=phi Tau | accessdate=2017-08-05 | postscript=. }}</ref>
<ref name="allen1899">{{citation | title=Star-Names and Their Meanings | last=Allen | first=Richard Hinckley | author-link=Richard Hinckley Allen | date=1899 | publisher=G. E. Stechert | publication-place=New York | page=413 }}</ref>
<ref name=rhoads1971>{{citation | url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720005197_1972005197.pdf | first1=Jack W. | last1=Rhoads | title=Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars | publisher=Jet Propulsion Laboratory, California Institute of Technology | date=November 15, 1971 | postscript=. }}</ref> </references>
{{Stars of Taurus|state=collapsed}}
Category:K-type giants Category:Double stars Tauri, Phi Category:Taurus (constellation) Category:Durchmusterung objects Tauri, 052 027382 020250 1348