24 Comae Berenices
Star in the constellation Coma Berenices
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24 Comae Berenices is a triple star system in the northern constellation of Coma Berenices. It is visible to the naked eye, with the brightest component being an orange-hued star with an apparent visual magnitude of 5.03.[2] The system is located at a distance of approximately 269 light-years from the Sun based on parallax, and is drifting further away with radial velocities of 3–5 km/s.[2]
Map showing location of 24 Comae Berenices | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Coma Berenices |
| A | |
| Right ascension | 12h 35m 07.76130s[1] |
| Declination | +18° 22′ 37.4133″[1] |
| Apparent magnitude (V) | 5.03[2] |
| B | |
| Right ascension | 12h 35m 06.34558s[1] |
| Declination | +18° 22′ 37.5320″[1] |
| Apparent magnitude (V) | 6.57[2] |
| Characteristics | |
| A | |
| Spectral type | K0II-III[3] |
| B−V color index | 1.152±0.018[2] |
| B | |
| Evolutionary stage | A9V[3] |
| B−V color index | 0.265±0.015[2] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +3.03±0.10[2] km/s |
| Proper motion (μ) | RA: −3.719[1] mas/yr Dec.: +23.106[1] mas/yr |
| Parallax (π) | 8.5745±0.1996 mas[1] |
| Distance | 380 ± 9 ly (117 ± 3 pc) |
| Absolute magnitude (MV) | 0.30[4] |
| B | |
| Radial velocity (Rv) | +4.90±0.50[2] km/s |
| Proper motion (μ) | RA: −2.320[1] mas/yr Dec.: +21.236[1] mas/yr |
| Parallax (π) | 8.8346±0.0695 mas[1] |
| Distance | 369 ± 3 ly (113.2 ± 0.9 pc) |
| Orbit[5] | |
| Primary | Ba |
| Name | Bb |
| Period (P) | 7.336673±0.000087 d |
| Semi-major axis (a) | 1.007±0.037 mas |
| Eccentricity (e) | 0.2585±0.0012 |
| Inclination (i) | 61.40±3.89° |
| Longitude of the node (Ω) | 136.17±2.86° |
| Periastron epoch (T) | 2,459,361.967±0.011 JD |
| Argument of periastron (ω) (primary) | 302.33±0.28° |
| Semi-amplitude (K1) (primary) | 68.16±0.09 km/s |
| Semi-amplitude (K2) (secondary) | 81.28±0.20 km/s |
| Details | |
| A | |
| Mass | 4.40[6] M☉ |
| Radius | 19.95+0.69 −2.58[1] R☉ |
| Luminosity | 173.3±4.6[1] L☉ |
| Surface gravity (log g) | 2.50[4] cgs |
| Temperature | 4,688+337 −79[1] K |
| Metallicity [Fe/H] | −0.09[7] dex |
| Ba | |
| Mass | 1.838±0.218[5] M☉ |
| Radius | 2.28±0.06[5] R☉ |
| Luminosity | 15.6±1.3[5] L☉ |
| Surface gravity (log g) | 3.86±0.01[5] cgs |
| Temperature | 7,630±120[5] K |
| Metallicity [Fe/H] | 0.54[8] dex |
| Rotational velocity (v sin i) | 14.5±1.5 km/s |
| Bb | |
| Mass | 1.541±0.184[5] M☉ |
| Radius | 1.70±0.07[5] R☉ |
| Luminosity | 7.2±0.9[5] L☉ |
| Surface gravity (log g) | 4.09±0.02[5] cgs |
| Temperature | 7,180±140[5] K |
| Metallicity [Fe/H] | 0.54[8] dex |
| Rotational velocity (v sin i) | 14.2±1.1[5] km/s |
| Other designations | |
| 24 Com, BD+19°2584, FK5 473, WDS 02338-2814 | |
| A: NSV 5748, GC 17147, HD 109511, HIP 61418, HR 4792, SAO 100160[9] | |
| B: GC 17146, HD 109510, HIP 61415, HR 4791, SAO 100159[10] | |
| Database references | |
| SIMBAD | A |
| B | |
This system can be resolved in a telescope as a pair of stars with an angular separation of 20.2″ along a position angle of 272°, as of 2018.[11] They share a common motion through space and thus appear to be physically associated,[12] with a wide projected separation of 1,400 AU or greater.[13] If they are bound in an orbit, the estimated period is approximately 28,000 years.[6]
The brighter member of this system is an aging giant or bright giant star with a stellar classification of K0II-III.[3] It has exhausted the supply of hydrogen at its core and expanded to 20[1] times the girth of the Sun. This is a suspected variable that has been recorded ranging in brightness from magnitude 4.98 down to 5.06.[14] The star is radiating 173[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,688 K.[1]
The fainter component at magnitude 6.57[2] is a double-lined spectroscopic binary with an orbital period of 7.33 days and an eccentricity of 0.26.[12] The primary member of this pair is an A-type main-sequence star with a stellar classification of A9V.[3] It is a metallic-lined Am star[15] with 2.2 times the radius of the Sun.[5] The stars radiate about 16 and 7 times the Sun's luminosity from its photosphere, respectively, at effective temperatures of 7,630 and 7180 K, respectively.[5] Both have relatively low projected rotational velocity of around 14 km/s,[5] and it is suspected the rotations of this binary system may be synchronized.[8] The system is a source for X-ray emission, which is most likely coming from the secondary.[16]