{{Short description|Star in the constellation Boötes}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Boötes IAU.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=π Boötis |x=455|y=825 }} | caption = Location of π Boötis (circled in red) }} {{Starbox observe | epoch = J2000 | ra = {{RA|14|40|43.559}}<ref name=GaiaDR3/> | dec = {{DEC|+16|25|05.98}}<ref name=GaiaDR3/> | appmag_v = 4.49<ref name=Anderson_Francis_2012/> {{nowrap|(4.893 + 5.761)}}<ref name=Hog2000/> | constell = [[Boötes (constellation)|Boötes]]<ref name=Anderson_Francis_2012/> }} {{Starbox character | class = {{nowrap|B9 IIIp (MnHgSi) + A6 V}}<ref name=Abt1984/> | r-i = −0.02{{cn|date=June 2025}} | v-r = | b-v = −0.002{{±|0.010}}<ref name=Anderson_Francis_2012/> | u-b = −0.31<ref name=Nicolet1978/> | variable = }} {{Starbox astrometry | radial_v = {{Val|−1.1|0.8}}<ref name=Gontcharov2006/> | prop_mo_ra = +13.922 | prop_mo_dec = +15.566 | pm_footnote = <ref name=GaiaDR3/> | parallax = 10.3357 | p_error = 0.1199 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = –0.39<ref name=North1998/> }} {{Starbox detail | source = | component1 = π<sup>1</sup> Boo | mass = {{Val|3.49|0.14}}<ref name=North1998/> | radius = {{Val|3.2|0.4}}<ref name=North1998/> | luminosity = 214<ref name=North1998/> | temperature = {{Val|12052|456|fmt=commas}}<ref name=prugniel2011/> | metal_fe = {{Val|+0.18|0.17}}<ref name=prugniel2011/> | gravity = {{Val|3.99|0.18}}<ref name=prugniel2011/> | rotational_velocity = 14.0<ref name=Ghazaryan2016/> | age_myr = | component2 = π<sup>2</sup> Boo | temperature2= 7504{{±|21|17}}<ref name=Royer_et_al_2024/> | gravity2 = 3.60{{±|0.01}}<ref name=Royer_et_al_2024/> | metal_fe2 = 0.580<ref name=Royer_et_al_2024/> | rotational_velocity2 = 144<ref name=Royer_et_al_2002/> }} {{Starbox catalog | names = {{odlist | B=π Boo | F=29 Boötis | BD=+17°2768 | HIP=71762 | ADS=9338 }}<ref name=SIMBAD/> | component1 = π<sup>1</sup> Boötis | names1 = {{odlist | HD=129174 | HR=5475 | SAO=101138 }} | component2 = π<sup>2</sup> Boötis | names2 = {{odlist | HD=129175 | HR=5476 | SAO=101139 }} }} {{Starbox reference | Simbad = pi.01+Boo |sn=π<sup>1</sup> Boo | Simbad2 = pi.02+Boo |sn2=π<sup>2</sup> Boo }} {{Starbox end}}
'''Pi Boötis''' is a candidate [[triple star]]<ref name=Shoeller2010/> system in the northern [[constellation]] of [[Boötes]]. Its name is a [[Bayer designation]] that is [[Latinisation of names|Latinized]] from '''π Boötis''', and abbreviated Pi Boo or π Boo. This system is visible to the [[naked eye]] as a point of light with a combined [[apparent visual magnitude]] of 4.50.<ref name=vanLeeuwen2007/> Based upon an annual [[stellar parallax|parallax shift]] of {{val|10.67|ul=mas}}<ref name=GaiaDR3/> as seen from Earth, it is located roughly 316 [[light year]]s from the [[Sun]].
The brighter primary, component π<sup>1</sup> Boötis, has a visual magnitude of 4.89<ref name=Hog2000/> and a [[stellar classification]] of {{nowrap|B9 IIIp (MnHgSi)}},<ref name=Abt1984/> which suggests it is an [[stellar evolution|evolved]] blue-white hued [[B-type star|B-type]] [[giant star]]. It is a [[chemically peculiar star]] of the [[HgMn star|HgMn type]],<ref name=Ghazaryan2016/> with a [[stellar spectrum|spectrum]] that displays anomalous overabundances of mercury, manganese, and silicon.<ref name=Abt1984/> This component is most likely a single-lined [[spectroscopic binary]] with an unknown companion.<ref name=Shoeller2010/>
Its magnitude 5.76<ref name=Hog2000/> visible companion, π<sup>2</sup> Boötis, is a white-hued [[A-type main-sequence star]] with a class of A6 V.<ref name=Abt1984/> It is spinning rapidly with a [[projected rotational velocity]] of 144 km/s.<ref name=Royer_et_al_2002/> As of 2010, the pair were separated by {{Val|5.537|0.003}} [[arcsecond]]s on the sky along a [[position angle]] of {{Val|110.5|0.5|u=°}}. This corresponds to a [[projected separation]] of {{Val|538.6|47.7|u=[[Astronomical Unit|AU]]}}. The odds that is a mere chance alignment is 0.85%.<ref name=Shoeller2010/>
Pi Boötis has the [[traditional Chinese star names|Chinese traditional star name]] 左攝提二 (Zuǒ shè tí èr).
==References== <references> <ref name=GaiaDR3>{{Cite Gaia DR3 | 1234645287617291520 | mode=cs2 | postscript=. }}</ref>
<ref name=Anderson_Francis_2012>{{Cite XHIP | 71762 | mode=cs2 | postscript=.}}</ref>
<ref name=vanLeeuwen2007>{{citation | title=Validation of the new Hipparcos reduction | last=van Leeuwen | first=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=Shoeller2010>{{citation | title=Multiplicity of late-type B stars with HgMn peculiarity | last1=Schöller | first1=M. | last2=Correia | first2=S. | last3=Hubrig | first3=S. | last4=Ageorges | first4=N. | journal=Astronomy and Astrophysics | display-authors=1 | volume=522 | id=A85 | pages=12 | date=November 2010 | doi=10.1051/0004-6361/201014246 | bibcode=2010A&A...522A..85S | arxiv=1010.3643| s2cid=119273467 }}</ref>
<ref name=Gontcharov2006>{{citation | last=Gontcharov | first=G. A. | title=Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system | journal=Astronomy Letters | volume=32| issue=11| pages=759–771| date=November 2006 | doi=10.1134/S1063773706110065 | bibcode=2006AstL...32..759G | arxiv=1606.08053 | s2cid=119231169 | postscript=. }}</ref>
<ref name=Hog2000>{{citation | title=The Tycho-2 catalogue of the 2.5 million brightest stars | journal=Astronomy and Astrophysics | postscript=. | volume=355 | pages=L27 | year=2000 | display-authors=1 | last1=Høg | first1=E. | last2=Fabricius | first2=C. | last3=Makarov | first3=V. V. | last4=Urban | first4=S. | last5=Corbin | first5=T. | last6=Wycoff | first6=G. | last7=Bastian | first7=U. | last8=Schwekendiek | first8=P. | last9=Wicenec | first9=A. | doi=10.1888/0333750888/2862 | bibcode=2000A&A...355L..27H }}</ref>
<ref name=Ghazaryan2016>{{citation | title=Statistical analysis from recent abundance determinations in HgMn stars | last1=Ghazaryan | first1=S. | last2=Alecian | first2=G. | journal=Monthly Notices of the Royal Astronomical Society | volume=460 | issue=2 | pages=1912–1922 | date=August 2016 | doi=10.1093/mnras/stw911 | bibcode=2016MNRAS.460.1912G | doi-access=free }}</ref>
<ref name=prugniel2011>{{citation | display-authors=1 | last1=Prugniel | first1=P. | last2=Vauglin | first2=I.| last3=Koleva | first3=M. | title=The atmospheric parameters and spectral interpolator for the MILES stars | journal=Astronomy & Astrophysics | volume=531| pages=A165| year=2011 | doi=10.1051/0004-6361/201116769 | postscript=. | arxiv=1104.4952 | bibcode=2011A&A...531A.165P | s2cid=54940439 }}</ref>
<ref name=Nicolet1978>{{citation | last=Nicolet | first=B. | title=Photoelectric photometric Catalogue of homogeneous measurements in the UBV System | journal=Astronomy and Astrophysics Supplement Series | volume=34 | pages=1–49 | year=1978 | bibcode=1978A&AS...34....1N | postscript=. }}</ref>
<ref name=Abt1984>{{citation | title=The nature of the visual companions of Ap and Am stars | last1=Abt | first1=H. A. | last2=Cardona | first2=O. | journal=Astrophysical Journal, Part 1 | postscript=. | volume=276 | date=January 1, 1984 | pages=266–269 | doi=10.1086/161610 | bibcode=1984ApJ...276..266A }}</ref>
<ref name=North1998>{{citation | last=North | first=P. | postscript=. | title=Do SI stars undergo any rotational braking? | journal=Astronomy and Astrophysics | volume=334 | pages=181–187 | date=June 1998 | bibcode=1998A&A...334..181N | arxiv=astro-ph/9802286 }}</ref>
<ref name=SIMBAD>{{cite simbad | title=pi Boo | access-date=2017-10-18 | mode=cs2 | postscript=. }}</ref>
<ref name=Royer_et_al_2002>{{citation | postscript=. | title=Rotational velocities of A-type stars II. Measurement of vsini in the northern hemisphere | display-authors=1 | last1=Royer | first1=F. | last2=Grenier | first2=S. | last3=Baylac | first3=M. O. | last4=Gómez | first4=A. E. | last5=Zorec | first5=J. | journal=Astronomy & Astrophysics | volume=393 | date=May 2002 | pages=897–912 | doi=10.1051/0004-6361:20020943 | s2cid=14070763 | bibcode=2002A&A...393..897R | arxiv=astro-ph/0205255 }}</ref>
<ref name=Royer_et_al_2024>{{citation | postscript=. | title=MELCHIORS. The Mercator Library of High Resolution Stellar Spectroscopy | last1=Royer | first1=P. | display-authors=etal | journal=Astronomy & Astrophysics | volume=681 | at=id. A107 | date=January 2024 | doi=10.1051/0004-6361/202346847 | arxiv=2311.02705 | bibcode=2024A&A...681A.107R }}</ref> </references>
==External links== * {{citation | title=Pi Bootis | first1=James B. | last1=Kaler | date=April 22, 2011 | work=Stars |publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/piboo.html | access-date=2017-10-13 | postscript=. }} * [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?HR%205475 HR 5475] * [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?CCDM%20J14407%2b1625A CCDM J14407+1625] * [http://aladin.u-strasbg.fr/AladinPreview?-c=14+40+43.5668%2B16+25+05.967&ident=HD+129174&submit=Aladin+previewer Image Pi Boötis]
{{Stars of Boötes|state=collapsed}}
{{DEFAULTSORT:Pi Bootis}} [[Category:B-type giants]] [[Category:A-type main-sequence stars]] [[Category:Mercury-manganese stars]] [[Category:Double stars]] [[Category:Triple stars]] [[Category:Boötes]] [[Category:Bayer objects|Bootis, Pi]] [[Category:Bright Star Catalogue objects|5745]] [[Category:Durchmusterung objects|BD+17 2768]] [[Category:Flamsteed objects|Bootis, 29]] [[Category:Henry Draper Catalogue objects|129174]] [[Category:Hipparcos objects|071762]]