{{Short description|Binary star system in the constellation Coma Berenices}} {{starbox begin}} {{Starbox image | image = {{Location mark | image = Coma Berenices constellation map.svg | width = 250 | alt = Map of the constellation Coma Berenices | float = center | mark = Red circle.svg | mark_width = 10 | x = 415 | y = 410 }} | caption = 23 Comae Berenices (circled) in the constellation Coma Berenices }} {{Starbox observe | constell = [[Coma Berenices]] | epoch = J2000 | ra = {{RA|12|34|51.08058}}<ref name=vanLeeuwen2007/> | dec = {{DEC|+22|37|45.3303}}<ref name=vanLeeuwen2007/> | appmag_v = 4.80<ref name=Anderson2012/> {{nowrap|(4.96 + 6.90)}}<ref name=Malkov2012/> }} {{Starbox character | class = A0IV<ref name=Cowley1969/> | b-v = {{Val|+0.012|0.015}}<ref name=Anderson2012/> | u-b = −0.01<ref name=EgUBV/> }} {{Starbox astrometry | radial_v = {{Val|−16.0|1.8}}<ref name=deBruijne2012/> | prop_mo_ra = −58.89<ref name=vanLeeuwen2007/> | prop_mo_dec = 28.31<ref name=vanLeeuwen2007/> | parallax = 10.52 | p_error = 0.52 | parallax_footnote = <ref name=vanLeeuwen2007/> | absmag_v = −0.08<ref name=Anderson2012/> }} {{Starbox orbit | reference = <ref name=Seymour2002/> | period = 33.04 | axis = 0.219 | inclination = 109.7 | node = 24.3 | periastron = [[Besselian year|B]]1964.62 | eccentricity = 0.898 | periarg = 214.5 }} {{Starbox detail | source = | mass = 2.15<ref name=David2015/> | radius = 3.0<ref name=cadars/> | luminosity = 104.00<ref name=Anderson2012/> | temperature = {{Val|9675|329|fmt=commas}}<ref name=David2015/> | gravity = 3.85<ref name=David2015/> | metal_fe = | rotational_velocity = 40<ref name=David2015/> | age_myr = 210<ref name=David2015/> }} {{Starbox catalog | names={{odlist | name=Phyllon Kissinou | F=23 Com | BD=+23°2475 | FK5=1323 | GC=17142 | HD=109485 | HIP=61394 | HR=4789 | SAO=82390 | WDS=J12349+2238 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad=23+Com }} {{Starbox end}}
'''23 Comae Berenices''', also named '''Phyllon Kissinou''',<ref name="IAU-CSN-new"/> is a [[binary star]]<ref name=Seymour2002/> system in the northern [[constellation]] of [[Coma Berenices]], situated a few degrees away from the [[North Galactic Pole]].<ref name=Straizys1989/> It is visible to the naked eye as a faint, white-hued point of light with an [[apparent visual magnitude]] of 4.80.<ref name=Anderson2012/> The system is located around 310 [[light year]]s away from the Sun, based on [[stellar parallax|parallax]].<ref name=vanLeeuwen2007/> It is moving closer to the Earth with a heliocentric [[radial velocity]] of −16 km/s.<ref name=deBruijne2012/>
The components of this system orbit each other with a [[orbital period|period]] of 33 years, a large [[orbital eccentricity|eccentricity]] of 0.9, and an angular [[semimajor axis]] of {{Val|0.219|ul=arcsecond}}.<ref name=Seymour2002/> The primary, designated component A, is a magnitude 4.96<ref name=Malkov2012/> star with a [[stellar classification]] of A0IV,<ref name=Cowley1969/> matching an [[A-type star|A-type]] [[subgiant star|subgiant]] that has exhausted the supply of hydrogen at its [[stellar core|core]] and is in the process of [[stellar evolution|evolving]] into a [[giant star|giant]]. Bychkov et al. (2009) list it as an [[Am star]] with an average [[stellar magnetic field|field strength]] of {{Val|26e−4|ul=T}}.<ref name=bychkov2009/>
The primary is 210<ref name=David2015/> million years old and is spinning with a [[projected rotational velocity]] of 40 km/s.<ref name=David2015/> It has 2.15<ref name=David2015/> times the [[mass of the Sun]] and about three<ref name=cadars/> times the [[Sun's radius]]. The star is radiating 104<ref name=Anderson2012/> times the [[luminosity of the Sun]] from its [[photosphere]] at an [[effective temperature]] of 9,675 K.<ref name=David2015/>
In Ptolemy's ''[[Almagest]]'', this star is described as "shaped like an [[ivy]] leaf" ({{lang|el|φύλλοv κισσίνου}}, ''phyllon kissinou''), presumably referring to the overall shape of the [[Coma Star Cluster]].<ref name=Ridpath/> Based on this, some modern sources have referred to it as Kissin (or Kissīn); this name has also been used for [[21 Comae Berenices]].<ref name=Allen1963/> The [[IAU Working Group on Star Names]] approved the name Phyllon Kissinou for this star on 16 May 2024 and it is now so entered in the IAU Catalog of Star Names;<ref name="IAU-CSN-new"/> since this is a binary system, the IAU has mentioned that the names Phyllon and Kissinou can be applied to the primary and secondary components, respectively.<ref name=WGSNreport2024/>
==References== <references> <ref name=SIMBAD>{{cite simbad|title=23 Com|access-date=8 September 2012}}</ref>
<ref name=Anderson2012>{{citation | 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 | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644 | postscript=. }}</ref>
<ref name=vanLeeuwen2007>{{cite journal | title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 }}</ref>
<ref name=Cowley1969>{{cite journal | last1=Cowley | first1=A. | last2=Cowley | first2=C. | last3=Jaschek | first3=M. | last4=Jaschek | first4=C. | title=A study of the bright A stars. I. A catalogue of spectral classifications | journal=Astronomical Journal | volume=74 | pages=375–406 | date=April 1969 | doi=10.1086/110819 | bibcode=1969AJ.....74..375C }}</ref>
<ref name=David2015>{{cite journal | last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A. | title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets | journal=The Astrophysical Journal | volume=804 | issue=2 | pages=146 | year=2015 | bibcode=2015ApJ...804..146D | arxiv=1501.03154 | doi=10.1088/0004-637X/804/2/146 | s2cid=33401607 }}</ref>
<ref name=Seymour2002>{{citation | title=Binary Star Orbits. II. Preliminary First Orbits for 117 Systems | last1=Seymour | first1=Diana M. | last2=Mason | first2=Brian D. | last3=Hartkopf | first3=William I. | last4=Wycoff | first4=Gary L. | journal=The Astronomical Journal | postscript=. | volume=123 | issue=2 | pages=1023–1038 | date=February 2002 | doi=10.1086/338441 | bibcode=2002AJ....123.1023S | s2cid=122326479 }}</ref>
<ref name=deBruijne2012>{{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=. }}</ref>
<ref name=Malkov2012>{{cite journal | last1=Malkov | first1=O. Yu. | last2=Tamazian | first2=V. S. | last3=Docobo | first3=J. A. | last4=Chulkov | first4=D. A. | title=Dynamical Masses of a Selected Sample of Orbital Binaries | journal=Astronomy and Astrophysics | volume=546 | id=A69 | pages=5 | date=2012 | doi=10.1051/0004-6361/201219774 | bibcode=2012A&A...546A..69M | doi-access=free }}</ref>
<ref name=cadars>{{cite journal | last1=Pasinetti Fracassini | first1=L. E. | last2=Pastori | first2=L. | last3=Covino | first3=S. | last4=Pozzi | first4=A. | title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) | edition=Third | journal=Astronomy and Astrophysics | volume=367 | issue=2 | pages=521–524 | date=February 2001 | display-authors=1 | doi=10.1051/0004-6361:20000451 | bibcode=2001A&A...367..521P | arxiv=astro-ph/0012289 | s2cid=425754 }}</ref>
<ref name=EgUBV>{{cite journal | last=Mermilliod | first=J.-C. | title=Compilation of Eggen's UBV data, transformed to UBV (unpublished) | journal=Catalogue of Eggen's UBV Data | date=1986 | bibcode= 1986EgUBV........0M }}</ref>
<ref name=Straizys1989>{{cite journal | title=Photoelectric photometry of bright stars in the vicinity of the North Galactic Pole | last1=Straizys | first1=V. | last2=Meistas | first2=E. | journal=Vilnius Astronomijos Observatorijos Biuletenis | volume=84 | page=26 | year=1989 | bibcode=1989VilOB..84...26S }}</ref>
<ref name=bychkov2009>{{citation | display-authors=1 | last1=Bychkov | first1=V. D. | last2=Bychkova | first2=L. V. | last3=Madej | first3=J. | title=Catalogue of averaged stellar effective magnetic fields - II. Re-discussion of chemically peculiar A and B stars | journal=Monthly Notices of the Royal Astronomical Society | volume=394 | issue=3 | pages=1338 | year=2009 | postscript=. | doi=10.1111/j.1365-2966.2008.14227.x | bibcode=2009MNRAS.394.1338B | s2cid=120268049 | doi-access=free }}</ref>
<ref name="IAU-CSN-new">{{cite web |title=IAU Catalog of Star Names |url=https://exopla.net/star-names/modern-iau-star-names/ |access-date=22 February 2025}}</ref>
<ref name=Allen1963>{{citation | first=Richard Hinckley | last=Allen | year=1963 | publisher=Dover Publications Inc. | page=171 | title=Star Names: Their Lore and Meaning | url=https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Coma_Berenices*.html | access-date=2019-11-01 | postscript=. }}</ref>
<ref name=Ridpath>{{cite web |last=Ridpath |first=Ian |author-link=Ian Ridpath |title=Star Tales - Coma Berenices |url=http://ianridpath.com/startales/comaberenices.html |access-date=1 August 2025}}</ref>
<ref name=WGSNreport2024>{{cite report |author=IAU Working Group on Star Names |title=Annual Report 2024 |url=https://exopla.net/wp-content/uploads/2025/04/2024_Annual-Report-WGSN_for2024.pdf}}</ref> </references>
{{Stars of Coma Berenices}}
[[Category:A-type subgiants]] [[Category:Am stars]] [[Category:Binary stars]] [[Category:Coma Berenices]] [[Category:Durchmusterung objects|BD+23 2475]] [[Category:Flamsteed objects|Comae Berenices, 23]] [[Category:Henry Draper Catalogue objects|109485]] [[Category:Hipparcos objects|061394]] [[Category:Bright Star Catalogue objects|4789]] [[Category:Stars with proper names|Phyllon Kissinou]]