# Omega Capricorni

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> Markdown URL: https://mediated.wiki/source/Omega_Capricorni.md
> Source: https://en.wikipedia.org/wiki/Omega_Capricorni
> Source revision: 1345152266
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{{short description|Star in the constellation Capricornus}}
{{Starbox begin
 | name = Omega Capricorni
}}
{{Starbox image
 | image=
{{Location mark
|image=Capricornus constellation map.svg|alt=|float=center|width=280
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link=ω Cap
|x=556|y=779
}}
 | caption = Location of ω Capricorni (circled)
}}{{Starbox observe
 | epoch       = [J2000.0](/source/J2000.0)
 | equinox     = [J2000.0](/source/J2000.0) ([ICRS](/source/International_Celestial_Reference_System))
 | constell    = [Capricornus](/source/Capricornus)
 | ra          = {{RA|20|51|49.291}}<ref name=GaiaDR3/>
 | dec         = {{DEC|−26|55|08.89}}<ref name=GaiaDR3/>
 | appmag_v    = +4.11<ref name=Nicolet1978/>
}}
{{Starbox character
 | type        = [horizontal branch](/source/horizontal_branch)<ref name=stock2018/>
 | class       = K4&nbsp;III<ref name=houk1979/>
 | b-v         = +1.64<ref name=Nicolet1978/>
 | u-b         = +1.93<ref name=Nicolet1978/>
 | r-i         = 
 | variable    = Suspected<ref name=AAVSO/>
}}
{{Starbox astrometry
 | radial_v    = {{Val|+9.1|1.4}}<ref name=Gontcharov2006/>
 | prop_mo_ra  = −9.016
 | prop_mo_dec = −2.048
 | pm_footnote = <ref name=GaiaDR3/>
 | parallax    = 5.8975
 | p_error     = 0.3064
 | parallax_footnote = <ref name=GaiaDR3/>
 | absmag_v    = −2.7<ref name=Mennessier1997/>
}}
{{Starbox detail
 | source      = 
 | mass        = {{Val|7.60|0.40|0.04}}<ref name=GaiaDR3/>
 | radius      = {{Val|93.2|4.9|3.8}}<ref name=GaiaDR3/>
 | luminosity  = {{Val|3194|344|278|fmt=commas}}<ref name=GaiaDR3/>
 | temperature = {{Val|4474|79|13|fmt=commas}}<ref name=GaiaDR3/>
 | gravity     = {{Val|0.84|0.15|0.02}}<ref name=GaiaDR3/>
 | metal_fe    = −0.24<ref name=McWilliam1990/>
 | rotational_velocity = 4.68<ref name=Hekker2007/>
 | age_myr     = {{Val|48.1|8.3}}<ref name=Tetzlaff2011/>
}}
{{Starbox catalog
 | names      = {{odlist | B=ω&nbsp;Cap | F=18&nbsp;Cap | CD=−27°15082 | FK5=1546 | HD=198542 | HIP=102978 | HR=7980 | SAO=189781 }}<ref name=SIMBAD/>
}}
{{Starbox reference
 | Simbad = ome+Cap
}}
{{Starbox end}}

'''Omega Capricorni''', is an orange-hued [star](/source/star) in the southern [constellation](/source/constellation) [Capricornus](/source/Capricornus), near the southern constellation border with [Microscopium](/source/Microscopium). Its name is a [Bayer designation](/source/Bayer_designation) that is [Latinized](/source/Romanization_of_Greek) from ω Capricorni, and abbreviated Omega Cap or ω Cap. This star is faintly visible to the naked eye, having an [apparent visual magnitude](/source/apparent_visual_magnitude) of +4.11.<ref name=Nicolet1978/> Based upon an annual [parallax](/source/parallax) shift of {{Val|5.9|ul=mas}} as seen from the Earth,<ref name=GaiaDR3/> it is located approximately {{convert|550|ly|pc|abbr=out|lk=on}} distant from the [Sun](/source/Sun). It is a candidate member of the [Ursa Major Moving Group](/source/Ursa_Major_Moving_Group)<ref name=Chupina2006/> and has a relatively high [peculiar velocity](/source/peculiar_velocity) of {{Val|25.7|1.9|u=km/s}}, making it is a possible [runaway star](/source/runaway_star).<ref name=Tetzlaff2011/>

In [Chinese](/source/Chinese_astronomy), {{lang|zh|天田}} ({{lang|zh-Latn|Tiān Tián}}), meaning ''[Celestial Farmland](/source/Ox_(Chinese_constellation))'', refers to an asterism consisting of ω Capricorni, [3 Piscis Austrini](/source/3_Piscis_Austrini), [24 Capricorni](/source/24_Capricorni) and [ψ Capricorni](/source/Psi_Capricorni).<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 [Chinese name](/source/Chinese_star_names) for ω Capricorni itself is {{lang|zh|天田二}} ({{lang|zh-Latn|Tiān Tián èr}}, {{langx|en|the First Star of Celestial Farmland}}.)<ref>{{in lang|zh}}  [http://aeea.nmns.edu.tw/2006/0607/ap060703.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 3 日] {{Webarchive|url=https://web.archive.org/web/20110521232833/http://aeea.nmns.edu.tw/2006/0607/ap060703.html |date=2011-05-21 }}</ref>

This is an [evolved](/source/stellar_evolution) [K-type](/source/K-type_star) [giant star](/source/giant_star) with a [stellar classification](/source/stellar_classification) of K4&nbsp;III,<ref name=houk1979/> and is a suspected [variable](/source/variable_star).<ref name=AAVSO/> With the supply of hydrogen at its [core](/source/stellar_core) exhausted, the star has expanded to about 93<ref name=GaiaDR3/> times the [radius of the Sun](/source/radius_of_the_Sun). It is 48<ref name=Tetzlaff2011/>&nbsp;million years old with 7.6 times the [mass of the Sun](/source/mass_of_the_Sun). Omega Capricorni is radiating 3,194 times the [luminosity of the Sun](/source/luminosity_of_the_Sun) from its bloated [photosphere](/source/photosphere) at an [effective temperature](/source/effective_temperature) of 4,474&nbsp;K.<ref name=GaiaDR3/> It is a [barium star](/source/barium_star),<ref name=Mennessier1997/> showing an overabundance of the [s-process](/source/s-process) elements. This suggests that Omega Capricorni has an orbiting [white dwarf](/source/white_dwarf) companion.<ref name=gomez1997/>

==References==
<references>

<ref name=GaiaDR3>{{cite DR3 | 6801963487915169920
 | mode=cs2 | access-date=2025-09-05 | postscript=. }}</ref>

<ref name=SIMBAD>{{cite simbad | title=ome Cap
 | mode=cs2 | access-date=2017-05-07 | postscript=. }}</ref>

<ref name=AAVSO>{{citation
 | title=NSV 13351
 | publisher=[American Association of Variable Star Observers](/source/American_Association_of_Variable_Star_Observers)
 | url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=51975
 | access-date=2017-05-07 | postscript=. }}</ref>

<ref name=Gontcharov2006>{{citation
 | last=Gontcharov | first=G. A.
 | title=Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system
 | journal=Astronomy Letters | postscript=.
 | volume=32| issue=11| pages=759–771| date=November 2006
 | doi = 10.1134/S1063773706110065 | s2cid=119231169
 | bibcode=2006AstL...32..759G | arxiv=1606.08053 }}</ref>

<ref name=Mennessier1997>{{citation
 | title=Barium stars, galactic populations and evolution.
 | display-authors=1 | last1=Mennessier | first1=M. O.
 | last2=Luri | first2=X. | last3=Figueras | first3=F.
 | last4=Gomez | first4=A. E. | last5=Grenier | first5=S.
 | last6=Torra | first6=J. | last7=North | first7=P.
 | journal=Astronomy and Astrophysics
 | volume=326 | pages=722–730 | date=October 1997
 | bibcode=1997A&A...326..722M | postscript=. }}</ref>

<ref name=gomez1997>{{citation
 | display-authors=1 | last1=Gomez | first1=A. E.
 | last2=Luri | first2=X. | last3=Grenier | first3=S.
 | last4=Prevot | first4=L. | last5=Mennessier | first5=M. O.
 | last6=Figueras | first6=F. | last7=Torra | first7=J.
 | title=Absolute magnitudes and kinematics of barium stars
 | journal=Astronomy and Astrophysics
 | volume=319 | pages=881 | year=1997
 | bibcode=1997A&A...319..881G | postscript=. }}</ref>

<ref name=McWilliam1990>{{citation
 | doi=10.1086/191527 | bibcode=1990ApJS...74.1075M
 | title=High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances
 | journal=The Astrophysical Journal Supplement Series
 | volume=74 | pages=1075 | year=1990 | postscript=.
 | last=McWilliam | first=Andrew | doi-access=free }}</ref>

<ref name=Chupina2006>{{citation
 | display-authors=1 | last1=Chupina | first1=N. V.
 | last2=Reva | first2=V. G. | last3=Vereshchagin | first3=S. V.
 | title=Kinematic structure of the corona of the Ursa Major flow found using proper motions and radial velocities of single stars
 | journal=Astronomy and Astrophysics | postscript=.
 | volume=451 | issue=3 | pages=909–916 | date=June 2006
 | doi=10.1051/0004-6361:20054009 | bibcode=2006A&A...451..909C | doi-access=free }} See table 7.</ref>

<ref name=Hekker2007>{{citation
 | last1=Hekker | first1=S. | last2=Meléndez | first2=J.
 | title=Precise radial velocities of giant stars. III. Spectroscopic stellar parameters
 | journal=[Astronomy and Astrophysics](/source/Astronomy_and_Astrophysics)
 | volume=475 | issue=3 | pages=1003–1009 | date=December 2007
 | doi=10.1051/0004-6361:20078233 | bibcode=2007A&A...475.1003H
 | arxiv=0709.1145 | s2cid=10436552 | postscript=. }}</ref>

<ref name=Tetzlaff2011>{{citation
 | display-authors=1 | last1=Tetzlaff | first1=N.
 | last2=Neuhäuser | first2=R. | last3=Hohle | first3=M. M.
 | title=A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun
 | journal=[Monthly Notices of the Royal Astronomical Society](/source/Monthly_Notices_of_the_Royal_Astronomical_Society)
 | volume=410 | issue=1 | pages=190–200 |date=January 2011
 | doi=10.1111/j.1365-2966.2010.17434.x | doi-access=free | bibcode=2011MNRAS.410..190T
 | arxiv=1007.4883 | s2cid=118629873 | postscript=. }}</ref>

<ref name=houk1979>{{citation
 | title=Michigan catalogue of two-dimensional spectral types for the HD stars
 | volume=3 | last=Houk | first=Nancy | postscript=.
 | publication-place=Ann Arbor, Michigan
 | publisher=Dept. of Astronomy, University of Michigan
 | date=1979 | bibcode=1982mcts.book.....H }}</ref>

<ref name=Nicolet1978>{{citation
 | last=Nicolet | first=B. | year=1978 | postscript=.
 | title=Photoelectric photometric Catalogue of homogeneous measurements in the UBV System
 | journal=Astronomy and Astrophysics Supplement Series
 | volume=34 | pages=1–49 | bibcode=1978A&AS...34....1N }}</ref>

<ref name=stock2018>{{cite journal |last1=Stock |first1=Stephan |last2=Reffert |first2=Sabine |last3=Quirrenbach |first3=Andreas |title=Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search |journal=Astronomy and Astrophysics |date=2018 |volume=616 |pages=A33 |doi=10.1051/0004-6361/201833111 |arxiv=1805.04094 |bibcode=2018A&A...616A..33S }}</ref>

</references>

{{Stars of Capricornus|state=collapsed}}

<!-- Properties -->
Category:K-type giants
Category:Suspected variables
Category:Barium stars
Category:Runaway stars
Category:Ursa Major moving group
<!-- Identifiers/constellation -->
Category:Capricornus
Capricorni, Omega
7980
Category:Durchmusterung objects
Capricorni, 18
198542
102978
Category:Horizontal-branch stars

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Adapted from the Wikipedia article [Omega Capricorni](https://en.wikipedia.org/wiki/Omega_Capricorni) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Omega_Capricorni?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.