23 Comae Berenices

23 Comae Berenices
Observation data
Epoch J2000      Equinox J2000
Constellation Coma Berenices
Right ascension 12h 34m 51.08058s
Declination +22° 37 45.3303
Apparent magnitude (V) 4.80 (4.96 + 6.90)
Characteristics
Spectral type A0IV
U−B color index −0.01
B−V color index +0.012±0.015
Astrometry
Radial velocity (Rv)−16.0±1.8 km/s
Proper motion (μ) RA: −58.89 mas/yr
Dec.: 28.31 mas/yr
Parallax (π)10.52±0.52 mas
Distance310 ± 20 ly
(95 ± 5 pc)
Absolute magnitude (MV)−0.08
Orbit
Period (P)33.04 yr
Semi-major axis (a)0.219″
Eccentricity (e)0.898
Inclination (i)109.7°
Longitude of the node (Ω)24.3°
Periastron epoch (T)B1964.62
Argument of periastron (ω)
(secondary)
214.5°
Details
Mass2.15 M
Radius3.0 R
Luminosity104.00 L
Surface gravity (log g)3.85 cgs
Temperature9,675±329 K
Rotational velocity (v sin i)40 km/s
Age210 Myr
Other designations
Phyllon Kissinou, 23 Com, BD+23°2475, FK5 1323, GC 17142, HD 109485, HIP 61394, HR 4789, SAO 82390, WDS J12349+2238
Database references
SIMBADdata

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 0.219. 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 26×10−4 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.