{{Short description|Binary star system in the constellation Coma Berenices}} {{Starbox begin}} {{Starbox image | image = {{Location mark | image=Coma Berenices constellation map.svg | float=center | width=260 | position=right | mark=Red circle.svg | mark_width=10 | mark_link=11 Com | x=528 | y=578 }} | caption = Location of 11 Comae Berenices (circled) }} {{Starbox observe | epoch = J2000 | constell = [[Coma Berenices]] | ra = {{RA|12|20|43.02577}}<ref name=GaiaDR3/> | dec = {{DEC|+17|47|34.3275}}<ref name=GaiaDR3/> | appmag_v = 4.72<ref name=Anderson2012/> {{nowrap|(4.89 + 12.9)}}<ref name=Eggleton2008/> }} {{Starbox character | type = [[red giant branch]]<ref name=GaiaDR3/> | class = K0 III<ref name="von Braun2014"/> or {{nowrap|G8+ III Fe-1}}<ref name=Keenan1989/> | b-v = {{Val|1.010|0.001}}<ref name=Anderson2012/> | u-b = | variable = }} {{Starbox astrometry | radial_v = {{Val|43.6|0.2}}<ref name=Anderson2012/> | prop_mo_ra = −109.426<ref name=GaiaDR3/> | prop_mo_dec = +88.930<ref name=GaiaDR3/> | parallax = 10.1677 | p_error = 0.1265 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = −0.02<ref name=Anderson2012/> }} {{Starbox detail | source = <ref name=jofre2015/> | mass = {{Val|1.66|0.21}} | radius = {{val|15.781|0.3444}}<ref name="von Braun2014"/> | luminosity = {{val|109.51|4.3256}}<ref name="von Braun2014"/> | gravity = {{Val|2.38|0.06}} | temperature = {{val|4670|10|fmt=commas}} | metal_fe = {{Val|−0.51|0.02}} | rotation = | rotational_velocity = | age_gyr = {{Val|1.53|0.54}} }} {{Starbox catalog | names = {{odlist | F=11 Com | BD=+18 2592 | FK5=2987 | HD=107383 | HIP=60202 | HR=4697 | SAO=100053 | WDS=J12207+1748 }}<ref name="Simbad"/> }} {{Starbox reference | Simbad = 11+Com }} {{Starbox end}}
'''11 Comae Berenices''' is a [[binary star]]<ref name=Eggleton2008/> system in the northern constellation of [[Coma Berenices]], located in the sky, east and slightly north of [[Denebola]] in [[Leo (constellation)|Leo]], but not nearly as far east as [[ε Virginis]] in [[Virgo (constellation)|Virgo]]. It is about a degree from the [[elliptical galaxy]] [[Messier 85|M85]] and two degrees north of the [[spiral galaxy]] [[Messier 100|M100]]. Based upon an annual [[stellar parallax|parallax shift]] of {{Val|10.7104|ul=mas}}, the star is located 305 [[light year]]s away from the Sun. It is visible to the naked eye as a faint, orange-hued star with an [[apparent visual magnitude]] of 4.72.<ref name=Anderson2012/> This body is moving away from the Sun with a heliocentric [[radial velocity]] of +44 km/s.<ref name=Anderson2012/>
The primary component is an aging [[K-type star|K-type]] [[giant star]] with a [[stellar classification]] of K0 III.<ref name="von Braun2014"/> It is a low metallicity star with an iron abundance about half that of the Sun.<ref name="von Braun2014"/> Keenan and McNeil (1989) found a class of {{nowrap|G8+ III Fe-1}},<ref name=Keenan1989/> showing an underabundance of iron in the [[stellar spectrum|spectrum]]. At the age of 1.5 billion years old with 1.7<ref name=jofre2015/> times the [[mass of the Sun]], it has exhausted the hydrogen at its [[stellar core|core]] and expanded to 15.8 times the [[Sun's radius]]. The star is radiating 110<ref name="von Braun2014"/> times the [[luminosity of the Sun]] from its swollen [[photosphere]] at an [[effective temperature]] of 4,670 K.<ref name=jofre2015/> It has a magnitude 12.9 companion star at an [[angular separation]] of {{Val|8.8|ul=arcsecond}} along a [[position angle]] of 44°, as of 2007.<ref name=WDSC2014/> == Planetary system == A substellar companion was discovered orbiting the primary star in 2007 using the [[radial velocity method]]. It has a [[orbital period|period]] of 326 days with minimum mass of about 19.4 Jupiter masses and is orbiting around {{Val|1.3|ul=AU}} from the host star with an [[orbital eccentricity|eccentricity]] of 0.23. The object's mass is well within the range of [[Deuterium fusion|deuterium-fusing]] [[brown dwarf]]s.<ref name="Liu2008"/><ref name=explanet/>
{{OrbitboxOnePlanet | exoplanet = [[11 Comae Berenices b|b]] | mass = ≥{{Val|19.4|1.5}} | period = {{Val|326.03|0.32}} | semimajor = {{Val|1.29|0.05}} | eccentricity = {{Val|0.231|0.005}} | year = 2007 }}
==References== <references> <ref name=GaiaDR3>{{cite Gaia DR3|3946945413106333696}}</ref>
<ref name=Anderson2012>{{Cite journal | 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 }}</ref>
<ref name=jofre2015>{{Cite journal | last1=Jofré | first1=E. | last2=Petrucci | first2=R. | last3=Saffe | first3=C. | last4=Saker | first4=L. | last5=de la Villarmois | first5=E. Artur | last6=Chavero | first6=C. | last7=Gómez | first7=M. | last8=Mauas | first8=P. J. D. | title=Stellar parameters and chemical abundances of 223 evolved stars with and without planets | display-authors=1 | journal=Astronomy & Astrophysics | volume=574 | pages=A50 | year=2015 | bibcode=2015A&A...574A..50J | arxiv=1410.6422 | doi=10.1051/0004-6361/201424474 | s2cid=53666931 }}</ref>
<ref name="Liu2008">{{Cite journal | title=A Substellar Companion to the Intermediate-Mass Giant 11 Comae | last1=Liu | first1=Y.-J. | last2=Sato | first2=Bun'ei | last3=Zhao | first3=G. | last4=Noguchi | first4=Kunio | last5=Wang | first5=H. | last6=Kambe | first6=Eiji | last7=Ando | first7=Hiroyasu | last8=Izumiura | first8=Hideyuki | last9=Chen | first9=Y.-Q. | last10=Okada | first10=Norio | last11=Toyota | first11=Eri | last12=Omiya | first12=Masashi | last13=Masuda | first13=Seiji | last14=Takeda | first14=Yoichi | last15=Murata | first15=Daisuke | last16=Itoh | first16=Yoichi | last17=Yoshida | first17=Michitoshi | last18=Kokubo | first18=Eiichiro | last19=Ida | first19=Shigeru | display-authors=1 | journal=The Astrophysical Journal | volume=672 | issue=1 | pages=553–557 | year=2008 | arxiv=0709.0645 | bibcode=2008ApJ...672..553L | doi=10.1086/523297 | s2cid=18039163 }}</ref>
<ref name="Simbad">{{cite simbad | title=* 11 Com | access-date=8 September 2012}}</ref>
<ref name="von Braun2014">{{cite journal | title=Stellar diameters and temperatures – V. 11 newly characterized exoplanet host stars | last1=von Braun | first1=Kaspar | last2=Boyajian | first2=Tabetha S. | last3=Van Belle | first3=Gerard T. | last4=Kane | first4=Stephen R. | last5=Jones | first5=Jeremy | last6=Farrington | first6=Chris | last7=Schaefer | first7=Gail | last8=Vargas | first8=Norm | last9=Scott | first9=Nic | last10=Ten Brummelaar | first10=Theo A. | last11=Kephart | first11=Miranda | last12=Gies | first12=Douglas R. | last13=Ciardi | first13=David R. | last14=López-Morales | first14=Mercedes | last15=Mazingue | first15=Cassidy | last16=McAlister | first16=Harold A. | last17=Ridgway | first17=Stephen | last18=Goldfinger | first18=P. J. | last19=Turner | first19=Nils H. | last20=Sturmann | first20=Laszlo | display-authors=1 | journal=Monthly Notices of the Royal Astronomical Society | volume=438 | issue=3 | pages=2413–2425 | year=2014 | arxiv=1312.1792 | bibcode=2014MNRAS.438.2413V | doi=10.1093/mnras/stt2360 | doi-access=free | s2cid=275132 }}</ref>
<ref name=explanet>{{cite encyclopedia | url=https://exoplanet.eu/catalog/11_com_b--882/ | encyclopedia=[[Extrasolar Planets Encyclopaedia]] | title=Planet 11 Com b| date=2023 }}</ref>
<ref name=WDSC2014>{{cite journal | display-authors=1 | last1=Mason | first1=B. D. | last2=Wycoff | first2=G. L. | last3=Hartkopf | first3=W. I. | last4=Douglass | first4=G. G. | last5=Worley | first5=C. E. | title=The Washington Visual Double Star Catalog | journal=The Astronomical Journal | volume=122 | issue=6 | pages=3466 | year=2014 | bibcode=2001AJ....122.3466M | doi=10.1086/323920 | doi-access=free }}</ref>
<ref name=Eggleton2008>{{cite journal | 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 | arxiv=0806.2878 | s2cid=14878976 }}</ref>
<ref name=Keenan1989>{{cite journal | title=The Perkins catalog of revised MK types for the cooler stars | journal=Astrophysical Journal Supplement Series | issn=0067-0049 | volume=71 | pages=245 | year=1989 | last1=Keenan | first1=Philip C. | last2=McNeil | first2=Raymond C. | bibcode= 1989ApJS...71..245K | doi=10.1086/191373 | s2cid=123149047 }}</ref> </references>
{{Stars of Coma Berenices}}
[[Category:G-type giants]] [[Category:Binary stars]] [[Category:Planetary systems with one confirmed planet]] [[Category:Coma Berenices]] [[Category:Durchmusterung objects]] [[Category:Flamsteed objects|Comae Berenices, 11]] [[Category:Henry Draper Catalogue objects|107383]] [[Category:Hipparcos objects|060202]] [[Category:Bright Star Catalogue objects|4697]]