View source for Astronomy:Xi Cephei

{{Short description|Star in the constellation Cepheus}}
{{Starbox begin 
| name = ξ Cephei
}}
{{Starbox image
 | image=
{{Location mark
|image=Cepheus constellation map.svg|alt=|float=center|width=240
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link= ξ Cephei
|x=664|y=876
}}
|caption=Location of  ξ Cephei (circled)
}}
{{Starbox observe 
| epoch = J2000 
| constell = [[Astronomy:Cepheus (constellation)|Cepheus]] 
| ra = {{RA|22|03|47.455}}<ref name="van Leeuwen2007"/>
| dec = {{DEC|+64|37|40.71}}<ref name="van Leeuwen2007"/> 
| appmag_v = 4.2<ref name=USNOB/>  {{nowrap|(4.45 + 4.60<ref name=WDS/>)}}
}}
{{Starbox character
| component = ξ Cephei A
| class = kA2.5hF2mF2(IV)<ref name=gray1989/>
}}
{{Starbox character|no_heading=y
| component = ξ Cephei B
| class = F8V<ref name=gray2001/>
}}
{{Starbox astrometry 
| radial_v =
| prop_mo_ra = {{Val|215.46|1.14}}<ref name="van Leeuwen2007"/> 
| prop_mo_dec = {{Val|91.06|0.97}}<ref name="van Leeuwen2007"/> 
| parallax = 38.10 
| p_error = 2.81 
| parallax_footnote = <ref name="Farrington2014"/>
| absmag_v = +1.79<ref name=Anderson2012/>
}}
{{Starbox orbit
 | reference = <ref name=Pourbaix2004/>
 | period_unitless = 810.9&nbsp;d
 | eccentricity = 0.46
 | periastron = 2438529.8&nbsp;JD
 | periarg = 106
 | k1 = 7.1
 | k2 = 19.9
}}
{{Starbox detail
 | component1  = ξ Cephei Aa
 | mass        = {{Val|1.045|0.031}}<ref name="Farrington2014"/>
 | luminosity  =
 | component2  = ξ Cephei Ab
 | mass2       = {{Val|0.408|0.066}}<ref name="Farrington2014"/>
}}
{{Starbox catalog 
| names = Kurhah, [[Astronomy:Flamsteed designation|17]]&nbsp;Cephei, BD+63°1802, CCDM&nbsp;J22038+2407, HIP&nbsp;108917, [[Astronomy:Bright Star Catalogue|HR]]&nbsp;8417, [[Astronomy:Smithsonian Astrophysical Observatory Star Catalog|SAO]]&nbsp;19827, [[Astronomy:Washington Double Star Catalog|WDS]]&nbsp;J22038+6438
| component1 = A
| names1 = HD 209790
| component2 = B
| names2 = HD 209791
}}
{{Starbox reference 
| Simbad = HR+8417 |sn=ξ
| Simbad2 = HD+209790 |sn2=A
| Simbad3 = HD+209791 |sn3=B
}}
{{Starbox end}}
'''Xi Cephei''' ('''ξ Cephei''', abbreviated '''Xi Cep''', '''ξ Cep''') is a multiple star system in the [[Astronomy:Constellation|constellation]] of [[Astronomy:Cepheus (constellation)|Cepheus]]. It is approximately 86 [[Astronomy:Light-year|light-year]]s from [[Astronomy:Earth|Earth]].<ref name="Farrington2014"/>

It consists of two [[Astronomy:Binary star|binary star]]s, designated Xi Cephei A and B, together with a more distant companion, Xi Cephei C. A's two components are themselves designated Xi Cephei Aa (officially named '''Kurhah''' {{IPAc-en|'|k|ɜːr|h|ə}}, the traditional name of the system)<ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=16 December 2017}}</ref> and Ab.

==Nomenclature==
''ξ Cephei'' ([[Social:Latinisation of names|Latinised]] to ''Xi Cephei'') is the system's [[Astronomy:Bayer designation|Bayer designation]]. The designations of the three constituents as ''ξ Cephei A'', ''B'' and ''C'', and those of ''A's'' components - ''ξ Cephei Aa'' and ''Ab'' - derive from the convention used by the Washington Multiplicity Catalog (WMC) for [[Astronomy:Star system|multiple star system]]s, and adopted by the [[Organization:International Astronomical Union|International Astronomical Union]] (IAU).<ref name="planetnaming">{{cite arXiv |title=On the naming convention used for multiple star systems and extrasolar planets |date=2010 |eprint=1012.0707 |class=astro-ph.SR |last1= Hessman |first1=F. V. |last2= Dhillon |first2=V. S. |last3= Winget |first3=D. E. |last4= Schreiber |first4=M. R. |last5= Horne |first5=K. |last6= Marsh |first6=T. R. |last7= Guenther |first7=E. |last8= Schwope |first8=A. |last9= Heber |first9=U. }}</ref>

Xi Cephei bore the traditional names ''Kurhah'', ''Alkirdah'' or ''Al Kirduh'',<ref>{{Cite web |url=http://www.icoproject.org/star.html |title=''Islamic Crescent Project:'' Star names |access-date=2010-12-08 |archive-date=2008-02-02 |archive-url=https://web.archive.org/web/20080202163504/http://www.icoproject.org/star.html |url-status=dead }}</ref> the name coming from Qazvini who gave ''Al Ḳurḥaḥ'' (''القرحة'' ''al-qurhah''), an [[Social:Arabic|Arabic]] word [[Biography:Christian Ludwig Ideler|Ideler]] translated as a white spot, or blaze, in the face of a horse. [[Astronomy:Star Names#Author|Allen]] indicates that Ideler felt this was not a proper name for a star, and suggested the name ''Al Ḳirdah'' (ألقردة ''al qírada'' "the Ape").<ref>{{cite book | last=Allen | first=R. H. | year=1963 |  title=Star Names: Their Lore and Meaning | url=https://archive.org/details/starnamestheirlo00alle/page/159 | access-date=2010-12-12 | edition=Reprint | publisher=Dover Publications Inc | location=New York | isbn=0-486-21079-0 | page=[https://archive.org/details/starnamestheirlo00alle/page/159 159] | url-access=registration }}</ref> In 2016, the [[Organization:International Astronomical Union|International Astronomical Union]] organized a [[Astronomy:IAU Working Group on Star Names|Working Group on Star Names]] (WGSN)<ref name="WGSN">{{citation
 | url=https://www.iau.org/science/scientific_bodies/working_groups/280/
 | title=IAU Working Group on Star Names (WGSN)
 | publisher=[[Organization:International Astronomical Union|International Astronomical Union]]
 | access-date=22 May 2016 | postscript=. }}</ref> to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.<ref name="TriRpt18">{{cite web | url=https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf | page=5 | title=WG Triennial Report (2015-2018) - Star Names |access-date=2018-07-14}}</ref> It approved the name ''Kurhah'' for the component Xi Cephei Aa on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN"/>

In [[Astronomy:Chinese astronomy|Chinese]], {{lang|zh|天鈎}} ({{lang|zh-Latn|Tiān Gōu}}), meaning ''Celestial Hook'', refers to an [[Astronomy:Asterism|asterism]] consisting of Xi Cephei, 4 Cephei, HD 194298, [[Astronomy:Eta Cephei|Eta Cephei]], [[Astronomy:Theta Cephei|Theta Cephei]], [[Astronomy:Alpha Cephei|Alpha Cephei]], 26 Cephei, [[Astronomy:Iota Cephei|Iota Cephei]] and [[Astronomy:Omicron Cephei|Omicron Cephei]].<ref>{{in lang|zh}} ''中國星座神話'', written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}.</ref> Consequently, the [[Astronomy:Chinese star names|Chinese name]] for Xi Cephei itself is {{lang|zh|天鈎六}} ({{lang|zh-Latn|Tiān Gōu liù}}, {{lang-en|the Sixth Star of Celestial Hook}}).<ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_h_l.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive |url=https://web.archive.org/web/20110129031951/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_h_l.htm |date=January 29, 2011 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref>

==Properties==

Xi Cephei A is a double-lined [[Astronomy:Spectroscopic binary|spectroscopic binary]] system with an [[Astronomy:Orbital period|orbital period]] of 810.9&nbsp;days and an [[Astronomy:Orbital eccentricity|eccentricity]] of 0.46.<ref name=Pourbaix2004/> The primary, component Aa, is a [[Chemistry:Chemically peculiar star|chemically peculiar]] [[Astronomy:Am star|Am star]], a probable [[Astronomy:Subgiant|subgiant]] with an [[Astronomy:Apparent magnitude|apparent magnitude]] of +4.29. Eight [[Arcsecond|arcsecond]]s away, Xi Cephei B is another spectroscopic binary. Xi Cephei C is a 13th magnitude star nearly two [[Arcminute|arcminute]]s away.<ref name=WDS/>

==References==
{{reflist|refs=

<ref name=gray2001>{{cite journal
 | doi=10.1086/319956 | bibcode=2001AJ....121.2148G| title=The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars| journal=The Astronomical Journal| volume=121| issue=4| pages=2148| year=2001| last1=Gray| first1=R. O| last2=Napier| first2=M. G| last3=Winkler| first3=L. I| doi-access=}}</ref>

<ref name=gray1989>{{cite journal
 | doi=10.1086/191315 | bibcode=1989ApJS...69..301G| title=The early F-type stars - Refined classification, confrontation with Stromgren photometry, and the effects of rotation| journal=The Astrophysical Journal Supplement Series| volume=69| pages=301| year=1989| last1=Gray| first1=R. O| last2=Garrison| first2=R. F}}</ref>

<ref name=Pourbaix2004>{{citation
 | title=S<sub>B<sup>9</sup></sub>: The ninth catalogue of spectroscopic binary orbits
 | journal=Astronomy & Astrophysics
 |display-authors=5 | last1=Pourbaix | first1=D.
 | last2=Tokovinin | first2=A. A. | last3=Batten | first3=A. H.
 | last4=Fekel | first4=F. C. | last5=Hartkopf | first5=W. I.
 | last6=Levato | first6=H. | last7=Morrell | first7=N. I.
 | last8=Torres | first8=G. | last9=Udry | first9=S.
 | volume=424 | issue=2 | pages=727–732 | date=2004
 | doi=10.1051/0004-6361:20041213 | bibcode=2004A&A...424..727P
 | arxiv=astro-ph/0406573 | s2cid=119387088
 | postscript=. }}</ref>

<ref name=Anderson2012>{{citation
 | title=XHIP: An extended hipparcos compilation
 | last1=Anderson | first1=E. | last2=Francis | first2=Ch.
 | journal=Astronomy Letters
 | volume=38 | issue=5 | pages=331 | year=2012
 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015
 | arxiv=1108.4971 | s2cid=119257644 | postscript=. }}</ref>

<ref name="Farrington2014">{{cite journal|title=Separated Fringe Packet Observations with the CHARA Array. II. omega Andromeda, HD 178911, and xi Cephei |last1=Farrington |first1=C. D. |last2=ten Brummelaar |first2=T. A. |last3=Mason |first3=B. D. |last4=Hartkopf |first4=W. I. |last5=Mourard |first5=D. |last6=Moravveji |first6=E. |last7=McAlister |first7=H. A. |last8=Turner |first8=N. H. |last9=Sturmann |first9=L. |last10=Sturmann |first10=J. |display-authors=1 |journal=The Astronomical Journal |volume=148 |issue=3 |pages=48 |year=2014 |arxiv=1407.0639 |bibcode=2014AJ....148...48F |doi=10.1088/0004-6256/148/3/48 |s2cid=12909818 }}</ref>

<ref name="van Leeuwen2007">{{cite journal | title=Validation of the new Hipparcos reduction | url=http://www.aanda.org/articles/aa/full/2007/41/aa8357-07/aa8357-07.html | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | year=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 }}[http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=I/311/hip2&recno=108548 Vizier catalog entry ]</ref>

<ref name=USNOB>{{cite journal|bibcode= 2003AJ....125..984M |title= The USNO-B Catalog |journal= The Astronomical Journal |volume= 125 |issue= 2 |pages= 984–993 |last1= Monet |first1= David G. |last2= Levine |first2= Stephen E. |last3= Canzian |first3= Blaise |last4= Ables |first4= Harold D. |last5= Bird |first5= Alan R. |last6= Dahn |first6= Conard C. |last7= Guetter |first7= Harry H. |last8= Harris |first8= Hugh C. |last9= Henden |first9= Arne A. |last10= Leggett |first10= Sandy K. |last11= Levison |first11= Harold F. |last12= Luginbuhl |first12= Christian B. |last13= Martini |first13= Joan |last14= Monet |first14= Alice K. B. |last15= Munn |first15= Jeffrey A. |last16= Pier |first16= Jeffrey R. |last17= Rhodes |first17= Albert R. |last18= Riepe |first18= Betty |last19= Sell |first19= Stephen |last20= Stone |first20= Ronald C. |last21= Vrba |first21= Frederick J. |last22= Walker |first22= Richard L. |last23= Westerhout |first23= Gart |last24= Brucato |first24= Robert J. |last25= Reid |first25= I. Neill |last26= Schoening |first26= William |last27= Hartley |first27= M. |last28= Read |first28= M. A. |last29= Tritton |first29= S. B. |year= 2003 |doi= 10.1086/345888 |arxiv = astro-ph/0210694 |s2cid= 55896673 }}</ref>

<ref name=WDS>{{cite journal|bibcode=2001AJ....122.3466M|title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog|journal=The Astronomical Journal|volume=122|issue=6|pages=3466|last1=Mason|first1=Brian D.|last2=Wycoff|first2=Gary L.|last3=Hartkopf|first3=William I.|last4=Douglass|first4=Geoffrey G.|last5=Worley|first5=Charles E.|year=2001|doi=10.1086/323920|doi-access=free}}</ref>
}}

{{Stars of Cepheus}}


{{DEFAULTSORT:Xi Cephei}}
[[Category:Cepheus (constellation)]]
[[Category:Bayer objects|Cephei, Xi]]
[[Category:A-type main-sequence stars]]
[[Category:Stars with proper names|Libertas]]
[[Category:Flamsteed objects|Cephei, 17]]
[[Category:Henry Draper Catalogue objects|209790 1]]
[[Category:Hipparcos objects|108917]]
[[Category:Durchmusterung objects|BD+63 1802]]
[[Category:Bright Star Catalogue objects|8417]]
[[Category:Spectroscopic binaries]]
[[Category:Am stars]]
[[Category:F-type main-sequence stars]]
[[Category:F-type subgiants]]

{{Sourceattribution|Xi Cephei}}