RS Sagittarii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 17m 36.246s |
| Declination | −34° 06′ 26.16″ |
| Apparent magnitude (V) | max: 6.01 min1: 6.97 min2: 6.28 |
| Characteristics | |
| Evolutionary stage | Main sequence + giant star |
| Spectral type | B3V + A0III |
| B−V color index | −0.096±0.012 |
| Variable type | Semidetached Algol |
| Astrometry | |
| Radial velocity (Rv) | 10.1±4.3 km/s |
| Proper motion (μ) | RA: −2.946 mas/yr Dec.: −10.190 mas/yr |
| Parallax (π) | 2.2918±0.0977 mas |
| Distance | 1,360±49 ly (418±15 pc) |
| Absolute magnitude (MV) | −1.58 (−4.02 + −1.09) |
| Orbit | |
| Period (P) | 2.4156835 days |
| Semi-major axis (a) | 17.32±0.02 R☉ |
| Eccentricity (e) | 0.0 |
| Inclination (i) | 82.829±0.074° |
| Periastron epoch (T) | 2,452,503.587±0.003 HJD |
| Semi-amplitude (K1) (primary) | 88.34±0.13 km/s |
| Semi-amplitude (K2) (secondary) | 271.53±0.13 km/s |
| Details | |
| Primary | |
| Mass | 8.846±0.015 M☉ |
| Radius | 5.524±0.022 R☉ |
| Luminosity | 3,700+90 −80 L☉ |
| Surface gravity (log g) | 3.900±0.005 cgs |
| Temperature | 19,000±100 K |
| Metallicity [Fe/H] | 0.0 dex |
| Rotational velocity (v sin i) | 115±5 km/s |
| Secondary | |
| Mass | 2.875±0.012 M☉ |
| Radius | 4.929±0.014 R☉ |
| Luminosity | 195+14 −13 L☉ |
| Surface gravity (log g) | 3.450±0.003 cgs |
| Temperature | 9,680±124 K |
| Metallicity [Fe/H] | 0.0 dex |
| Rotational velocity (v sin i) | 90±5 km/s |
| Other designations | |
| RS Sgr, CD−34°12673, GC 24947, HD 167647, HIP 89637, HR 6833, SAO 209959, WDS J18176-3406A | |
| Database references | |
| SIMBAD | data |
RS Sagittarii is an eclipsing binary star system in the southern constellation of Sagittarius, abbreviated RS Sgr. It is a double-lined spectroscopic binary with an orbital period of 2.416 days, indicating that the components are too close to each other to be individually resolved. The system has a combined apparent visual magnitude of 6.01, which is bright enough to be faintly visible to the naked eye. During the primary eclipse the brightness drops to magnitude 6.97, while the secondary eclipse is of magnitude 6.28. The distance to this system is 418 parsecs (1,360 light-years).