{{Short description|Star in the constellation Boötes}} {{Starbox begin | name=Xi Boötis }} {{Starbox image | image = {{Location map|100x100 |AlternativeMap=Boötes IAU.svg |caption= |alt=Diagram showing star positions and boundaries of the Boötes constellation and its surroundings |width=250 |lat=37 |long=40.8 |mark=Cercle rouge 100%.svg | marksize=12 |float=center }} | caption = Location of ξ Boötis (circled) }} {{Starbox observe | epoch = J2000 | ra = {{RA|14|51|23.37993}}<ref name=GaiaDR3a/> | dec = {{DEC|+19|06|01.6994}}<ref name=GaiaDR3a/> | appmag_v = {{nowrap|4.675 + 6.816}}<ref name="Høg_et_al_2000"/> | constell = [[Boötes]] }} {{Starbox character | class = {{nowrap|G8 Ve + K4 Ve}}<ref name=Levato_Abt_1978/> | r-i = | v-r = | b-v = 0.725/1.165<ref name="Høg_et_al_2000"/> | u-b = | variable = [[BY Draconis variable|BY Dra]]<ref name=Samus_et_al_2017/> }} {{Starbox astrometry | component1 = ξ Boo A | radial_v = {{val|+1.59|0.12}}<ref name=GaiaDR3a/> | prop_mo_ra = 127.468 | prop_mo_dec = −40.569 | pm_footnote = <ref name=GaiaDR3a/> | parallax = 148.0695 | p_error = 0.1317 | parallax_footnote = <ref name=GaiaDR3a/> | absmag_v = {{Val|5.54|0.007}}<ref name=park2013/> | component2 = ξ Boo B | radial_v2 = {{val|+2.31|0.13}}<ref name=GaiaDR3b/> | prop_mo_ra2 = 133.376 | prop_mo_dec2 = −182.059 | pm_footnote2 = <ref name=GaiaDR3b/> | parallax2 = 148.1793 | p_error2 = 0.0546 | parallax_footnote2 = <ref name=GaiaDR3b/> | absmag_v2 = }} {{Starbox visbin | reference = <ref name=Izmailov2025/> | period_unitless = {{val|152.46|0.07}} years | axis = {{val|4.91985|0.00266|fmt=commas}} | eccentricity = {{val|0.5141|0.0005|fmt=commas}} | inclination = {{val|140.538|0.065}} | node = {{val|167.938|0.162}} | periarg = {{val|24.015|0.258}} | periastron = {{val|2061.90|0.09|fmt=none}} }} {{Starbox detail | component1 = ξ Boo A | mass = {{val|0.88|0.03}}<ref name=Karovicova/> | radius = {{val|0.817|0.007}}<ref name=Karovicova/> | luminosity = {{val|0.562|0.036}}<ref name=Karovicova/> | temperature = {{val|5545|92|fmt=commas}}<ref name=Karovicova/> | metal_fe = {{val|−0.10|0.04}}<ref name=Karovicova/> | rotation = {{val|6.2|u=days}}<ref name=apj717_2_1279/> | age_myr = 200<ref name=apj687_2_1264/> | gravity = {{val|4.561|0.017}}<ref name=Karovicova/> | component2 = ξ Boo B | mass2 = {{val|0.66|0.07}}<ref name=aaa338_455/> | radius2 = 0.61<ref name=apj717_2_1279/> | luminosity_visual2 = 0.061 | temperature2 = {{val|4350|150|fmt=commas}}<ref name=aaa338_455/> | rotation2 = 11.5<ref name=apj717_2_1279/> days }} {{Starbox catalog | names = {{odlist | B=ξ Boo | F=37 Boötis | BD=+19°2870 | GCTP=3360.00 | GJ=566 | HD=131156 | HIP=72659 | HR=5544 | SAO=101250 | WDS=J14514+1906 | GC=19991 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad=*+ksi+Boo | sn=The system | Simbad2=*+ksi+Boo+A | sn2=A | Simbad3=*+ksi+Boo+B | sn3=B | ARICNS=01171 }} {{Starbox end}}
'''Xi Boötis''' is a [[binary star]]<ref name=aaa338_455/> system in the northern [[constellation]] of [[Boötes]]. Its name is a [[Bayer designation]] that is [[Romanization of Greek|Latinised]] from ξ Boötis, and abbreviated Xi Boo or ξ Boo. This is the nearest visible star in the [[constellation]] [[Boötes]]. The brighter, primary component of the pair has a typical [[apparent visual magnitude]] of 4.70, making it visible to the [[naked eye]]. Based on [[stellar parallax|parallax]] measurements, it is located at a distance of {{convert|22.0|ly|pc|abbr=off|lk=on}} from [[Earth]]. The pair are drifting further from the Sun with a [[radial velocity]] of +2 km/s.<ref name=GaiaDR3a/>
==Properties== [[File:XiBooLightCurve.png|thumb|left|A light curve for Xi Bootis, showing the average of the [[Photometric_system#Photometric_letters|b and y]] magnitudes as a function of time. Adapted from Lockwood ''et al.'' (2007)<ref name="Lockwood"/>]] The primary star in this system is a [[G-type main-sequence star]] with a [[stellar classification]] of G8 Ve,<ref name=Levato_Abt_1978/> where the 'e' notation indicates [[emission line]]s in the [[stellar spectrum|spectrum]]. It is a [[BY Draconis variable]] with an [[apparent magnitude]] that varies from +4.52 to +4.67 with a period just over 10 days long. The [[magnetic activity]] in the star's [[chromosphere]] varies with time, but no activity cycle has been found (as of 2019).<ref name=Finley_et_al_2019/> It has 88% of [[solar mass|the mass]] and 82% of [[solar radius|the radius]] of the Sun, but shines with just 56% the [[Sun's luminosity]].<ref name=Karovicova/>
The secondary component is a smaller [[K-type main-sequence star]] with a class of K4 Ve.<ref name=Levato_Abt_1978/> It has 66% of the Sun's mass and 61% of the Sun's radius. The star is radiating just 6.1% of the luminosity of the Sun from its [[photosphere]] at an [[effective temperature]] of 4,350 K.<ref name=aaa338_455/> This gives it an apparent visual magnitude of 6.8,<ref name="Høg_et_al_2000"/> which by itself would be a challenge to view with the naked eye. As of 2019, it is located at an [[angular separation]] of {{val|5.20|ul=arcsecond}} from the primary, along a [[position angle]] of 298°.<ref name=Mason_et_al_2014/>
The pair follow a wide, highly elliptical orbit around their common [[barycenter]], completing an orbit every 152.5 years.<ref name=Izmailov2025/> [[Radial velocity]] measurements taken of the primary as part of an [[extrasolar planet]] search show a linear trend in the velocities that is likely due to the secondary star.<ref name="Howard2016"/> The pair can be resolved using a small telescope. The binary system contains two of the closest young [[solar-type star]]s to the Sun, with a system age of about 200 million years old.<ref name=apj687_2_1264/>
The primary star, component A, has been identified as a candidate for possessing a [[Kuiper belt|Kuiper-like belt]],<ref name=hinshaw19970203/> based on [[infrared]] observations. The estimated minimum mass of this dust disk is 2.4 times the mass of the Earth's [[Moon]]. (Compare to the value of 8.2 lunar masses for the Kuiper belt.)<ref name=aj125_6_3334/>
A necessary condition for the existence of a planet in this system are stable zones where the object can remain in orbit for long intervals. For hypothetical planets in a circular orbit around the individual members of this star system, this maximum orbital radius is computed to be {{val|3.8|ul=AU}} for the primary and 3.5 AU for the secondary. A planet orbiting outside of both stars would need to be at least 108 AU distant.<ref name=mnras427_4_2723/>
==See also== * [[List of nearest stars by spectral type#List of nearest K-type stars|List of nearest K-type stars]]
==References== <references> <ref name=SIMBAD>{{cite simbad | title=Xi Boo | access-date=2025-05-31 | postscript=. | mode = cs2 }}</ref>
<ref name=GaiaDR3a>{{Cite Gaia DR3|1237090738916392704}}</ref>
<ref name=GaiaDR3b>{{Cite Gaia DR3|1237090738916392832}}</ref>
<ref name=Karovicova>{{cite journal | doi=10.1051/0004-6361/202141833 | title=Fundamental stellar parameters of benchmark stars from CHARA interferometry -- II. Dwarf stars | year=2022 | display-authors=1 | last1=Karovicova | first1=I. | last2=White | first2=T. R. | last3=Nordlander | first3=T. | last4=Casagrande | first4=L. | last5=Ireland | first5=M. | last6=Huber | first6=D. | journal=Astronomy & Astrophysics | volume=658 | pages=A47 | arxiv=2109.06203 | bibcode=2022A&A...658A..47K | s2cid=219558406}}</ref>
<ref name=park2013>{{cite journal | display-authors=1 | last1=Park | first1=Sunkyung | last2=Kang | first2=Wonseok | last3=Lee | first3=Jeong-Eun | last4=Lee | first4=Sang-Gak | title=Wilson-Bappu Effect: Extended to Surface Gravity | journal=The Astronomical Journal | volume=146 | issue=4 | pages=73 | year=2013 | doi=10.1088/0004-6256/146/4/73 | bibcode=2013AJ....146...73P | arxiv=1307.0592 | s2cid=119187733 }}</ref>
<ref name=apj717_2_1279>{{cite journal | last1=Wood | first1=Brian E. | last2=Linsky | first2=Jeffrey L. | title=Resolving the ξ Boo Binary with Chandra, and Revealing the Spectral Type Dependence of the Coronal "FIP Effect" | journal=The Astrophysical Journal | volume=717 | issue=2 | pages=1279–1290 |date=July 2010 | doi=10.1088/0004-637X/717/2/1279 | bibcode=2010ApJ...717.1279W |arxiv = 1005.3281 | s2cid=53394680 }}</ref>
<ref name="Lockwood">{{cite journal | display-authors=1 |last1=Lockwood |first1=G. W. |last2=Skiff |first2=B. A. |last3=Henry |first3=Gregory W. |last4=Henry |first4=Stephen |last5=Radick |first5=R. R. |last6=Baliunas |first6=S. L. |last7=Donahue |first7=R. A. |last8=Soon |first8=W. |title=Patterns of Photometric and Chromospheric Variation among Sun-like Stars: A 20 Year Perspective |journal=The Astrophysical Journal Supplement Series |date=July 2007 |volume=171 |issue=1 |pages=260–303 |doi=10.1086/516752 |arxiv=astro-ph/0703408 |bibcode=2007ApJS..171..260L |s2cid=18775739 |url=https://iopscience.iop.org/article/10.1086/516752/pdf |access-date=1 July 2022}}</ref>
<ref name=apj687_2_1264>{{cite journal | last1=Mamajek | first1=Eric E. | last2=Hillenbrand | first2=Lynne A. | title=Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics | journal=The Astrophysical Journal | volume=687 | issue=2 | pages=1264–1293 |date=November 2008 | doi=10.1086/591785 | bibcode=2008ApJ...687.1264M |arxiv = 0807.1686 | s2cid=27151456 }}</ref>
<ref name=Izmailov2025>{{Cite journal |last1=Izmailov |first1=Igor |last2=Khovritchev |first2=Maxim |date=January 2025 |title=New Orbital Parameters of 850 Wide Visual Binary Stars and Their Statistical Properties |journal=Research in Astronomy and Astrophysics |language=en |volume=25 |issue=1 |pages=015016 |doi=10.1088/1674-4527/ad9da3 |bibcode=2025RAA....25a5016I |issn=1674-4527}}</ref>
<ref name=hinshaw19970203>{{cite book | last=Hinshaw | first=Gary | date=February 3, 1997 | url=http://ssc.spitzer.caltech.edu/documents/SRD.pdf | title=Science Requirements Document | publisher=NASA JPL | access-date=2006-08-10 | archive-url=https://web.archive.org/web/20060529023819/http://ssc.spitzer.caltech.edu/documents/SRD.pdf <!-- Bot retrieved archive --> | archive-date=2006-05-29 }}</ref>
<ref name=aj125_6_3334>{{cite journal | display-authors=1 | first1=E. K. | last1=Holmes | first2=H. M. | last2=Butner | first3=S. B. | last3=Fajardo-Acosta | first4=L. M. | last4=Rebull | title=A Survey of Nearby Main-Sequence Stars for Submillimeter Emission | journal=The Astronomical Journal | year=2003 | volume=125 | issue=6 | pages=3334–3343 | doi=10.1086/375202 | bibcode=2003AJ....125.3334H|doi-access=free}}</ref>
<ref name=aaa338_455>{{cite journal | display-authors=1 | last1=Fernandes | first1=J. | last2=Lebreton | first2=Y. | last3=Baglin | first3=A. | last4=Morel | first4=P. | title=Fundamental stellar parameters for nearby visual binary stars: eta Cas, XI Boo, 70 OPH and 85 Peg. Helium abundance, age and mixing length parameter for low mass stars | journal=Astronomy and Astrophysics | volume=338 | pages=455–464 |date=October 1998 | bibcode=1998A&A...338..455F }}</ref>
<ref name=mnras427_4_2723>{{cite journal | display-authors=1 | last1=Jaime | first1=Luisa G. | last2=Pichardo | first2=Barbara | last3=Aguilar | first3=Luis | title=Regions of dynamical stability for discs and planets in binary stars of the solar neighbourhood | journal=Monthly Notices of the Royal Astronomical Society | volume=427 | issue=4 | pages=2723–2733 | date=December 2012 | bibcode=2012MNRAS.427.2723J | doi=10.1111/j.1365-2966.2012.21839.x | doi-access=free | arxiv=1208.2051 | s2cid=118570249 }}</ref>
<ref name="Howard2016">{{cite journal | title=Limits on Planetary Companions from Doppler Surveys of Nearby Stars | last1=Howard | first1=Andrew W. | last2=Fulton | first2=Benjamin J. | journal=Publications of the Astronomical Society of the Pacific | volume=128 | issue=969 | at=114401 | year=2016 | arxiv=1606.03134 | bibcode=2016PASP..128k4401H | doi=10.1088/1538-3873/128/969/114401 | s2cid=118503912 }}</ref>
<ref name=Finley_et_al_2019>{{cite journal | title=The Effect of Magnetic Variability on Stellar Angular Momentum Loss. II. The Sun, 61 Cygni A, ɛ Eridani, ξ Bootis A, and τ Bootis A | display-authors=1 | last1=Finley | first1=Adam J. | last2=See | first2=Victor | last3=Matt | first3=Sean P. | journal=The Astrophysical Journal | volume=876 | issue=1 | id=44 | pages=14 | date=May 2019 | doi=10.3847/1538-4357/ab12d2 | arxiv=1903.09871 | bibcode=2019ApJ...876...44F | s2cid=85500195 | doi-access=free }}</ref>
<ref name=Mason_et_al_2014>{{cite journal | 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 | doi=10.1086/323920 | url=http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/wds | accessdate=2015-07-22 | doi-access=free }}</ref>
<ref name=Levato_Abt_1978>{{cite journal | title=Spectral types in the Ursa Major stream | last1=Levato | first1=H. | last2=Abt | first2=H. A. | journal=Publications of the Astronomical Society of the Pacific | volume=90 | pages=429−433 | date=August 1978 | doi=10.1086/130352 | bibcode=1978PASP...90..429L | doi-access=free }}</ref>
<ref name=Samus_et_al_2017>{{cite journal | title=General Catalogue of Variable Stars | 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. | version=GCVS 5.1 | journal=Astronomy Reports | year=2017 | volume=61 | issue=1 | pages=80–88 | doi=10.1134/S1063772917010085 | bibcode=2017ARep...61...80S }}</ref>
<ref name="Høg_et_al_2000">{{Cite journal | title=The Tycho-2 catalogue of the 2.5 million brightest stars | 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. | journal=Astronomy and Astrophysics | language=en | volume=355 | pages=L27–L30 | date=March 2000 | bibcode=2000A&A...355L..27H |issn=0004-6361 }}</ref> </references>
==External links== * [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?HR%205544 HR 5544] {{Webarchive|url=https://web.archive.org/web/20110519193744/http://webviz.u-strasbg.fr/viz-bin/VizieR-S?HR%205544 |date=2011-05-19 }} * [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?GJ%20566%20B GJ 566 B] {{Webarchive|url=https://web.archive.org/web/20110519193931/http://webviz.u-strasbg.fr/viz-bin/VizieR-S?GJ%20566%20B |date=2011-05-19 }} * [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?CCDM%20J14513%2b1906A CCDM J14513+1906] {{Webarchive|url=https://web.archive.org/web/20110519194125/http://webviz.u-strasbg.fr/viz-bin/VizieR-S?CCDM%20J14513+1906A |date=2011-05-19 }} * [http://aladin.u-strasbg.fr/AladinPreview?-c=SV*+SVS++2491&ident=SV*+SVS++2491&submit=Aladin+previewer Image Xi Boötis]
{{Stars of Boötes}}
<!-- Properties --> [[Category:G-type main-sequence stars]] [[Category:K-type main-sequence stars]] [[Category:Solar-type stars|Bootis, Xi]] [[Category:BY Draconis variables]] [[Category:Binary stars]] <!-- Other --> [[Category:Boötes]] [[Category:Bayer objects|Bootis, Xi]] [[Category:Bright Star Catalogue objects|5544]] [[Category:Durchmusterung objects|BD+19 2870]] [[Category:Flamsteed objects|Bootis, 37]] [[Category:Gliese and GJ objects|0566]] [[Category:Henry Draper Catalogue objects|131156]] [[Category:Hipparcos objects|072659]]