Kappa Arietis
Binary star system in the constellation Aries
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Kappa Arietis is a binary star system in the northern constellation of Aries. Its name is a Bayer designation that is Latinized from κ Arietis, and abbreviated Kappa Ari or κ Ari. The combined apparent visual magnitude of the pair is 5.02,[3] making the system bright enough for it to be dimly visible to the naked eye as a white-hued point of light. It is located approximately 181 light-years from the Sun based on parallax,[2] and is drifting further away with a radial velocity of +11.5 km/s.[4]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Aries[1] |
| Right ascension | 02h 06m 33.92497s[2] |
| Declination | +22° 38â² 53.9476â³[2] |
| Apparent magnitude (V) | 5.02[3] |
| Characteristics | |
| Spectral type | A2m[1] |
| UâB color index | +0.11[3] |
| BâV color index | +0.12[3] |
| Astrometry | |
| Radial velocity (Rv) | +11.5[4] km/s |
| Proper motion (μ) | RA: +20.348[2] mas/yr Dec.: â35.671[2] mas/yr |
| Parallax (Ï) | 18.0292±0.3092 mas[2] |
| Distance | 181 ± 3 ly (55.5 ± 1.0 pc) |
| Absolute magnitude (MV) | 1.30[1] |
| Orbit[5] | |
| Period (P) | 15.2938 d |
| Eccentricity (e) | 0.61 |
| Periastron epoch (T) | 2,421,844.121 JD |
| Argument of periastron (Ï) (secondary) | 358.3° |
| Semi-amplitude (K1) (primary) | 34.5 km/s |
| Semi-amplitude (K2) (secondary) | 35.4 km/s |
| Details | |
| Mass | 2.09±0.31[6] Mâ |
| Radius | 2.32±0.08[6] Râ |
| Luminosity | 24.4±1.3[6] Lâ |
| Surface gravity (log g) | 4.03±0.07[6] cgs |
| Temperature | 8,421±125[6] K |
| Metallicity [Fe/H] | +0.18[7] dex |
| Rotational velocity (v sin i) | 18[8] km/s |
| Other designations | |
| κ Ari, 12 Arietis, BD+21°279, GC 2527, HD 12869, HIP 9836, HR 613, SAO 75146, PM 91364[9] | |
| Database references | |
| SIMBAD | data |
The binary nature of this system was announced in 1918 by Lick Observatory. It is a double-lined spectroscopic binary with an orbital period of 15.3 days and an eccentricity of 0.61.[5] Both components displaying the spectral properties of an Am, or metallic-lined star. They have nearly the same brightness and their mass ratio is 1.03; very close to equal.[7]