Global InformationKappa2 Sagittarii information
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 20h 23m 53.17666s[1] |
| Declination | −42° 25′ 22.3376″[1] |
| Apparent magnitude (V) | +5.64[2] (6.04 + 7.12)[3] |
| Characteristics | |
| Spectral type | A5 V[4] (A1 + A6)[5] |
| U−B color index | +0.099[2] |
| B−V color index | +0.192[2] |
| Astrometry | |
| Radial velocity (Rv) | +2.6[6] km/s |
| Proper motion (μ) | RA: −13.07[1] mas/yr Dec.: +13.64[1] mas/yr |
| Parallax (π) | 10.47 ± 0.50 mas[1] |
| Distance | 310 ± 10 ly (96 ± 5 pc) |
| Absolute magnitude (MV) | 1.03/2.35[5] |
| Orbit[7] | |
| Period (P) | 700 yr |
| Semi-major axis (a) | 2.032″ |
| Eccentricity (e) | 0.401 |
| Inclination (i) | 80° |
| Longitude of the node (Ω) | 40.7° |
| Periastron epoch (T) | 1912.00 |
| Argument of periastron (ω) (secondary) | 177.3° |
| Details | |
| κ2 Sgr A | |
| Mass | 1.85[8] M☉ |
| Luminosity | 38[9] L☉ |
| Surface gravity (log g) | 4.03[8] cgs |
| Temperature | 7,990±272[8] K |
| Age | 833[8] Myr |
| Other designations | |
κ2 Sgr, CD−42° 14847, HD 193807, HIP 100591, HR 7787, SAO 230184, WDS J20239-4225[10] | |
| Database references | |
| SIMBAD | data |
Kappa2 Sagittarii (κ2 Sagittarii) is a binary star[3] system in the zodiac constellation of Sagittarius. It is visible to the naked eye with a combined apparent visual magnitude of +5.64.[2] Based upon an annual parallax shift of 10.47 mas as seen from Earth,[1] this system is located around 310 light years from the Sun. They are receding with a radial velocity of +2.6 km/s.[6]
This is a visual binary system with the components orbiting each other over a period of roughly 700 years, having an eccentricity of 0.4 and a semimajor axis of 2 arc seconds.[7] The pair have a combined spectral type that matches an A-type main sequence star with a stellar classification of A5 V.[4] The individual components are of estimated types A1 and A6.[5] The primary member, component A, is a magnitude 6.04[3] star with 1.85[8] times the mass of the Sun. It is radiating 38[9] times the Sun's luminosity from its photosphere at an effective temperature of about 7,990 K.[8] The companion, component B, is visual magnitude 7.12.[3]
There are two visual companions: component C is a magnitude 14.3 star at an angular separation of 18.6 arc seconds along a position angle of 266°, as of 2000; component D is magnitude 14.0 with a separation of 29.8 arc seconds along a position angle of 219°, also as of 2000.[11]
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