theta Ursae Minoris
{{Short description|Suspected binary star in the constellation Ursa Minor}}
{{Starbox begin
| name=θ Ursae Minoris
}}
{{Starbox image
| image=
{{Location mark
|image=Ursa Minor constellation map.svg|alt=|float=center|width=260
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link=θ UMi
|x=436|y=522
}}
|caption=Location of θ Ursae Minoris (circled)
}}
{{Starbox observe
| epoch = J2000
| dec = {{DEC|+77|20|57.6199}}
| appmag_v = 4.982{{cite book
| 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.
| chapter=Tycho Star Catalogs: The 2.5 Million Brightest Stars | journal=Astronomy and Astrophysics
| volume=355 | pages=L27 | year=2000
| bibcode=2000A&A...355L..27H | doi=10.1888/0333750888/2862 | isbn=0-333-75088-8 }}
| constell = Ursa Minor
}}
{{Starbox character
| u-b =
}}
{{Starbox astrometry
| radial_v = {{Val|−25.3|0.5}}{{citation
| last1=de Bruijne | first1=J. H. J. | last2=Eilers | first2=A.-C.
| title=Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project
| journal=Astronomy & Astrophysics
| volume=546 | id=A61 | pages=14 | date=October 2012
| doi=10.1051/0004-6361/201219219 | bibcode=2012A&A...546A..61D
| arxiv=1208.3048 | s2cid=59451347 | postscript=. }}
| prop_mo_ra = {{Val|−47.55|0.37}}
| prop_mo_dec = {{Val|+5.33|0.43}}
| parallax= 3.81
| p_error=0.37
| parallax_footnote={{citation
| first=F. | last=van Leeuwen
| title=Validation of the new Hipparcos reduction
| journal=Astronomy and Astrophysics
| volume=474 | issue=2 | pages=653–664
| date=November 2007 | bibcode=2007A&A...474..653V
| doi=10.1051/0004-6361:20078357 | arxiv=0708.1752
| s2cid=18759600
| postscript=.
}}
}}
{{Starbox detail
| mass=
| radius = 96{{citation |last1=McDonald |first1=I. |last2=Zijlstra |first2=A. A. |last3=Watson |first3=R. A. |date=2017-10-01 |title=Fundamental parameters and infrared excesses of Tycho-Gaia stars |journal=Monthly Notices of the Royal Astronomical Society |volume=471 |issue=1 |pages=770–791 |doi=10.1093/mnras/stx1433 |doi-access=free |issn=0035-8711|arxiv=1706.02208 }} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/MNRAS/471/770&RAJ2000=232.853872 theta UMi' database entry] at VizieR.
| luminosity = 1,618{{cite journal
| display-authors=1 | last1=McDonald | first1=I.
| last2=Zijlstra | first2=A. A. | last3=Boyer | first3=M. L.
| title=Fundamental Parameters and Infrared Excesses of Hipparcos Stars
| journal=Monthly Notices of the Royal Astronomical Society
| volume=427 | issue=1 | pages=343–57 | date=2012
| bibcode=2012MNRAS.427..343M | arxiv=1208.2037
| doi=10.1111/j.1365-2966.2012.21873.x | doi-access=free | s2cid=118665352 }}
| temperature = {{Val|3962|36|fmt=commas}}
| metal_fe = {{Val|+0.18|0.06}}{{citation
| title=The atmospheric parameters and spectral interpolator for the MILES stars
| display-authors=1 | last1=Prugniel | first1=Ph.
| last2=Vauglin | first2=I. | last3=Koleva | first3=M.
| journal=Astronomy & Astrophysics
| volume=531 | id=A165 | pages=25 | date=July 2011
| doi=10.1051/0004-6361/201116769 | bibcode=2011A&A...531A.165P
| arxiv=1104.4952 | s2cid=54940439 | postscript=. }}
| rotational_velocity =
| age_gyr =
}}
{{Starbox catalog
| names = {{odlist | B=θ UMi | F=15 Ursae Minoris | BD=+77°592 | FK5=3229 | HD=139669 | HIP=76008 | HR=5826 | SAO=8274 }}{{cite simbad | title=* tet UMi | access-date=16 June 2014}}
}}
{{Starbox reference
|Simbad=tet+UMi
}}
{{Starbox end}}
Theta Ursae Minoris, Latinized from θ Ursae Minoris, is a suspected binary star system that is visible to the naked eye in the northern circumpolar constellation of Ursa Minor. It is roughly 860 light years from Earth with an apparent visual magnitude of 5.0. The system is moving closer to the Sun with a radial velocity of −25 km/s.
This is a probable spectroscopic binary with two roughly equal components.
{{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 }} The spectrum matches a stellar classification of K5-III CN0.5, which would normally indicate an evolved, orange-hued giant star of type K that has a mild overabundance of cyanogen in the outer atmosphere. The estimated diameter is around 96 times that of the Sun, and it is radiating approximately 1,618 times the Sun's luminosity from an expanded photosphere at an effective temperature of 3,962 K.
Photometry from the Hipparcos satellite mission shows that θ Ursae Minoris varies in brightness by a few hundredths of a magnitude. It is listed as NSV 20342 in the New Catalogue of Suspected Variable Stars.{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}
References
{{reflist|refs=
| title=Population Synthesis in the Blue. IV. Accurate Model Predictions for Lick Indices and UBV Colors in Single Stellar Populations
| last1=Schiavon | first1=Ricardo P.
| journal=The Astrophysical Journal Supplement Series
| volume=171 | issue=1 | pages=146–205 | date=July 2007
| doi=10.1086/511753 | bibcode=2007ApJS..171..146S
| arxiv=astro-ph/0611464 | s2cid=13946698 | postscript=. }}
}}
{{Stars of Ursa Minor}}
{{DEFAULTSORT:Theta Ursae Minoris}}