23 Comae Berenices
{{Short description|Binary star system in the constellation Coma Berenices}}
{{starbox begin}}
{{Starbox observe
| constell = Coma Berenices
| epoch = J2000
| dec = {{DEC|+22|37|45.3303}}
| appmag_v = 4.80 {{nowrap|(4.96 + 6.90)}}
}}
{{Starbox character
}}
{{Starbox astrometry
| radial_v = {{Val|−16.0|1.8}}
| parallax = 10.52
| p_error = 0.52
}}
{{Starbox orbit
| period = 33.04
| axis = 0.219
| inclination = 109.7
| node = 24.3
| periastron = B1964.62
| eccentricity = 0.898
| periarg = 214.5
}}
{{Starbox detail
| source =
| temperature = {{Val|9675|329|fmt=commas}}
| metal_fe =
}}
{{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 }}
}}
{{Starbox reference
| Simbad=23+Com
}}
{{Starbox end}}
23 Comae Berenices, also named Phyllon Kissinou, is a binary star system in the northern constellation of Coma Berenices, situated a few degrees away from the North Galactic Pole. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.80. The system is located around 310 light years away from the Sun, based on parallax. It is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.
The components of this system orbit each other with a period of 33 years, a large eccentricity of 0.9, and an angular semimajor axis of {{Val|0.219|ul=arcsecond}}. The primary, designated component A, is a magnitude 4.96 star with a stellar classification of A0IV, matching an A-type subgiant that has exhausted the supply of hydrogen at its core and is in the process of evolving into a giant. Bychkov et al. (2009) list it as an Am star with an average field strength of {{Val|26e−4|ul=T}}.
The primary is 210 million years old and is spinning with a projected rotational velocity of 40 km/s. It has 2.15 times the mass of the Sun and about three times the Sun's radius. The star is radiating 104 times the luminosity of the Sun from its photosphere at an effective temperature of 9,675 K.
In Ptolemy's Almagest, this star is named Phyllon Kissinou (φύλλοv κισσίνου), meaning an ivy leaf. It is also known by the shorter name Kissin (or Kissīn); this name has also been used for 21 Comae Berenices. 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.
References
{{reflist|refs=
{{cite simbad|title=23 Com|access-date=8 September 2012}}
| 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=. }}
| 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 }}
| 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 }}
| 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 }}
| 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 }}
| 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=. }}
| 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 }}
| 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
}}
| 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 }}
| 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 }}
| 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 }}
| 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=. }}
}}
{{Stars of Coma Berenices}}
{{DEFAULTSORT:23 Comae Berenices}}