11 Ursae Minoris
{{Short description|Star in the constellation Ursa Minor}}
{{Starbox begin
| name = 11 Ursae Minoris
}}
{{Starbox observe
| epoch = J2000.0
| constell = Ursa Minor
| dec = {{DEC|+71|49|26.0473}}
}}
{{Starbox character
| appmag_1_passband = B
| appmag_2_passband = J
| appmag_3_passband = H
| appmag_3 = {{Val|1.931|0.192}}
| appmag_4_passband = K
| appmag_4 = {{Val|1.701|0.198}}
| r-i =
| v-r =
| u-b =
| variable =
}}
{{Starbox astrometry
| radial_v = {{Val|−17.80|0.12}}
| prop_mo_ra = +4.073
| prop_mo_dec = +9.477
| parallax = 7.9260
| p_error = 0.1249
}}
{{Starbox detail
| mass = {{val|2.60|0.48|0.44}}
| temperature = {{val|4253|25|fmt=commas}}
| habitable_inner = {{val|15.63|0.57}} AU
| habitable_outer = {{val|30.65|1.10}} AU
| age_gyr = {{val|639|507|278}}
}}
{{Starbox catalog
| names = {{odlist | F=11 UMi | BD=+72°678 | FK5=1140 | HD=136726 | HIP=74793 | HR=5714 | SAO=8207 | GCRV=8864 | PPM=8870 }}{{cite simbad | title=11 UMi | access-date=8 September 2012}}
}}
{{Starbox reference
| Simbad = 11+UMi
| NSTED = 11+UMi
| EPE = 11+UMi
}}
{{Starbox end}}
11 Ursae Minoris is a single star located approximately 410 light years away in the northern circumpolar constellation of Ursa Minor. The star is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.15. It is moving closer to the Earth with a heliocentric radial velocity of −17.8 km/s.
This is an aging K-type giant star with a stellar classification of K4 III. It is 600 million years old with twice the mass of the Sun. As a consequence of exhausting the hydrogen at its core, the star has expanded to 29 times the Sun's radius. It is radiating 250 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,253 K.
11 Ursae Minoris is sometimes named Pherkard or Pherkad Minor, the later name to distinguish it from Pherkad (Major) which is γ Ursae Minoris. It has also been designated as γ1 Ursae Minoris, in which case the brighter Pherkad is called γ2 Ursae Minoris, but these names are rarely used. 11 Ursae Minoris is the Flamsteed designation.
11 Ursae Minoris has a detected planet discovered in August 2009.
Planetary system
11 Ursae Minoris b was discovered during a radial velocity survey of 62 K type Red giant stars using the 2m Alfred Jensch telescope of the Thuringian State Observatory in Germany.
A newer mass measurement of the host star implies a larger planetary mass of {{val|14.15|1.23|ul=Jupiter mass}}, which would make 11 Ursae Minoris b a low-mass brown dwarf.
{{OrbitboxPlanet begin
}}
{{OrbitboxPlanet
| exoplanet = b
| mass = {{val|p=≥|14.15|1.23}}
| period = 516.22 ± 3.25
| semimajor = 1.54 ± 0.07
| eccentricity = 0.08 ± 0.03
}}
{{Orbitbox end}}
References
{{Reflist|refs=
{{cite DR3|1696798367260229376}}
| 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 | arxiv=1108.4971
| doi=10.1134/S1063773712050015 | s2cid=119257644 }}
| 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 | postscript=.
| bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 }}
| title=Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer
| last1=Baines | first1=Ellyn K. | last2=Armstrong | first2=J. Thomas | last3=Schmitt | first3=Henrique R. | last4=Zavala | first4=R. T. | last5=Benson | first5=James A. | last6=Hutter | first6=Donald J. | last7=Tycner | first7=Christopher | last8=Belle | first8=Gerard T. van
| display-authors=1 | journal=The Astronomical Journal
| volume=155 | at=30 | year=2018
| issue=1 | arxiv=1712.08109 | bibcode=2018AJ....155...30B
| doi=10.3847/1538-3881/aa9d8b | s2cid=119427037 | doi-access=free }}
{{Cite journal |last=Soubiran |first=C. |last2=Creevey |first2=O. |last3=Lagarde |first3=N. |last4=Brouillet |first4=N. |last5=Jofré |first5=P. |last6=Casamiquela |first6=L. |last7=Heiter |first7=U. |last8=Aguilera–Gómez |first8=C. |last9=Vitali |first9=S. |last10=Worley |first10=C. |last11=de Brito Silva |first11=D. |date=February 2024 |title=Gaia FGK benchmark stars: Fundamental Teff and log ɡ of the third version (Corrigendum) |journal=Astronomy & Astrophysics |volume=693 |pages=C3 |doi=10.1051/0004-6361/202453050e |arxiv=2310.11302 |issn=0004-6361}}
| title=Planetary companions around the K giant stars 11 Ursae Minoris and HD 32518
| url=http://www.aanda.org/articles/aa/full_html/2009/39/aa11702-09/aa11702-09.html
| last1=Döllinger | first1=P. | last2=Hatzes | first2=A. P.
| last3=Pasquini | first3=L. | last4=Guenther | first4=E. W.
| last5=Hartmann | first5=M. | display-authors=1
| journal=Astronomy and Astrophysics
| volume=505 | issue=3 | pages=1311–1317 | year=2009
| arxiv=0908.1753 | bibcode=2009A&A...505.1311D
| doi=10.1051/0004-6361/200911702 | s2cid=9686080
}}
| last1=Kostjuk | first1=N. D.
| title=VizieR Online Data Catalog: HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index (Kostjuk, 2002)
| journal=VizieR On-line Data Catalog: IV/27A. Originally Published in: Institute of Astronomy of Russian Academy of Sciences (2002)
| volume=4027 | year=2004
| bibcode=2004yCat.4027....0K }}
}}
External links
- {{cite encyclopedia |url=http://exoplanet.eu/star.php?st=11+UMi |archive-url=https://web.archive.org/web/20090819025425/http://exoplanet.eu/star.php?st=11+UMi |url-status=dead |archive-date=August 19, 2009 |title=Notes for star 11 UMi |author=Jean Schneider |date=2011 |encyclopedia=Extrasolar Planets Encyclopaedia |access-date=30 September 2011}}
{{Stars of Ursa Minor}}
{{Sky|15|17|05.8886|+|71|49|26.044|389.8}}