Kappa Ursae Majoris

{{short description|Binary star in the constellation Ursa Major}}

{{Starbox begin

| name=Kappa Ursae Majoris

}}

{{Starbox image

| image={{Location map|100x100

|AlternativeMap=Ursa Major IAU.svg

|caption=

|width=320

|lat=55.75 |long=73.5

|mark=Cercle rouge 100%.svg | marksize=12

|float=center

}}| caption=Location of κ Ursae Majoris (circled)

}}

{{Starbox observe

| epoch=J2000.0

| constell=Ursa Major

| ra={{RA|09|03|37.52762}}

| dec={{DEC|+47|09|23.4890}}

| appmag_v={{nowrap|3.56 (4.16 + 4.54)}}

}}

{{Starbox character

| class={{nowrap|A0 IV-V + A0 V}}

}}

{{Starbox astrometry

| radial_v =

| prop_mo_ra = −36.19

| prop_mo_dec = −55.40

| parallax = 9.10

| p_error = 0.50

| parallax_footnote =

| absmag_v = −1.63

}}

{{Starbox orbit

| reference =

| period_unitless = {{Val|13007.2|9.7|fmt=commas|u=d}}

| axis = {{nowrap|0.18194 ± 0.00025}}

| eccentricity = {{Val|0.5584|0.0015}}

| inclination = {{Val|109.410|0.066}}

| node = {{Val|105.641|0.080}}

| periastron = {{nowrap|50404 ± 12}}

| periarg = {{Val|355.63|0.36}}

}}

{{Starbox detail

| component1 = κ UMa A

| mass = {{Val|3.79|0.12}}

| radius = 7.87

| gravity =

| metal_fe =

| age_gyr =

| luminosity =

| temperature = 9,060

| rotational_velocity = 201

}}

{{Starbox catalog

| names= Alkaphrah, {{odlist | B=κ UMa | F=12 Ursae Majoris | BD=+47°1633 | FK5=341 | HD=77327 | HIP=44471 | HR=3594 | SAO=42661 | CCDM=J09036+4709AB | GC=12503 | IDS=08568+4733 | PPM=50987 | WDS=J09036+4709AB }}

}}

{{Starbox reference

| Simbad=kap+UMa

}}

Kappa Ursae Majoris (κ Ursae Majoris, abbreviated Kappa UMa, κ UMa) is a binary star in the constellation of Ursa Major. With a combined apparent magnitude of +3.60, the system is approximately 358 light-years from Earth.

The two components are designated Kappa Ursae Majoris A (officially named Alkaphrah {{IPAc-en|æ|l|'|k|æ|f|r|@}}, a traditional name of the system){{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=16 December 2017}} and B.

Nomenclature

κ Ursae Majoris (Latinised to Kappa Ursae Majoris) is the system's Bayer designation. The designations of the two components as Kappa Ursae Majoris A and B derives from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).{{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. }}

The traditional name of the system is Alkafzah (corrupted to Alkaphrah or El Koprah), from the Arabic القفزة al-qafzah "the leap".Allen (1899) (Cf. Alula Borealis and Alula Australis.)

In 2016, the IAU organized a Working Group on Star Names (WGSN){{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|access-date=22 May 2016}} to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.{{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}} It approved the name Alkaphrah for the component Kappa Ursae Majoris A on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.

In Chinese, {{lang|zh|三台}} ({{lang|zh-Latn|Sān Tái}}), meaning Three Steps, refers to an asterism consisting of Kappa Ursae Majoris, Iota Ursae Majoris, Lambda Ursae Majoris, Mu Ursae Majoris, Nu Ursae Majoris and Xi Ursae Majoris. Consequently, the Chinese name for Kappa Ursae Majoris itself is {{lang|zh|上台二}} ({{lang|zh-Latn|Shàng Tái èr}}, {{langx|en|Star of Second Upper Step}}).{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0606/ap060621.html (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 21 日] {{Webarchive|url=https://web.archive.org/web/20160303180027/http://aeea.nmns.edu.tw/2006/0606/ap060621.html |date=2016-03-03 }}

Properties

Both components of the binary star are white A-type main sequence dwarfs. They have apparent magnitudes of +4.2 and +4.5.{{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}} The orbital period of the binary is 35.6 years (13,007.2 days), and the two stars are separated by 0.18 arcseconds. An infrared excess indicates a debris disk with a mean temperature of 165 K is orbiting the primary at a separation of {{Val|55.2|ul=AU}}.

References

{{reflist|refs=

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{{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 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | bibcode=2008MNRAS.389..869E | postscript=. |arxiv = 0806.2878 | s2cid=14878976 }}

{{citation | last1=Edwards | first1=T. W. | title=MK classification for visual binary components | journal=Astronomical Journal | volume=81 | pages=245–249 |date=April 1976 | doi=10.1086/111879 | bibcode=1976AJ.....81..245E }}

{{cite journal | display-authors=1 | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99 | year=1966 | bibcode=1966CoLPL...4...99J }}

{{citation | title=CCDM J09036+4709AB -- Double or multiple star | work=SIMBAD Astronomical Object Database | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Kappa+Ursae+Majoris | access-date=2012-03-26 }}

{{citation | display-authors=1 | last1=Muterspaugh | first1=Matthew W. | last2=Hartkopf | first2=William I. | last3=Lane | first3=Benjamin F. | last4=O'Connell | first4=J. | last5=Williamson | first5=M. | last6=Kulkarni | first6=S. R. | last7=Konacki | first7=Maciej | last8=Burke | first8=Bernard F. | last9=Colavita | first9=M. M. | last10=Shao | first10=M. | last11=Wiktorowicz | first11=Sloane J. | title=The Phases Differential Astrometry Data Archive. II. Updated Binary Star Orbits and a Long Period Eclipsing Binary | journal=The Astronomical Journal | volume=140 | issue=6 | pages=1623–1630 |date=December 2010 | doi=10.1088/0004-6256/140/6/1623 | bibcode=2010AJ....140.1623M |arxiv = 1010.4043 | s2cid=6030289 }}

{{citation | display-authors=1 | last1=Hartkopf | first1=W. I. | last2=Mason | first2=B. D. | last3=Worley | first3=C. E. | date=June 30, 2006 | title=Sixth Catalog of Orbits of Visual Binary Stars | publisher=United States Naval Observatory | url=http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6 | access-date=2017-06-02 | postscript=. | archive-date=2017-08-01 | archive-url=https://web.archive.org/web/20170801102553/http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6 | url-status=dead }}

{{citation

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| 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=. }}

{{citation

| title=A Comprehensive Census of Nearby Infrared Excess Stars

| last1=Cotten | first1=Tara H. | last2=Song | first2=Inseok

| journal=The Astrophysical Journal Supplement Series

| doi=10.3847/0067-0049/225/1/15 | postscript=.