4 Sagittarii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 17h 59m 47.55646s |
| Declination | −23° 48′ 58.0130″ |
| Apparent magnitude (V) | 4.74 |
| Characteristics | |
| Spectral type | B9V |
| U−B color index | −0.03 |
| B−V color index | -0.05 |
| Astrometry | |
| Radial velocity (Rv) | 64.33±1.32 km/s |
| Proper motion (μ) | RA: −0.900 mas/yr Dec.: −51.149 mas/yr |
| Parallax (π) | 7.9879±0.3689 mas |
| Distance | 410 ± 20 ly (125 ± 6 pc) |
| Absolute magnitude (MV) | −0.77 |
| Details | |
| Mass | 3.23 M☉ |
| Radius | 5.53 R☉ |
| Luminosity | 240 L☉ |
| Temperature | 9,661 K |
| Rotational velocity (v sin i) | 149 km/s |
| Other designations | |
| 4 Sgr, CD−23°13731, FK5 3430, GC 24483, HD 163955, HIP 88116, HR 6700, SAO 186061, GSC 06841-01403 | |
| Database references | |
| SIMBAD | data |
4 Sagittarii is a suspected astrometric binary star system in the zodiac constellation of Sagittarius, located approximately 410 light-years away based on parallax. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.74. The system is moving away from the Earth with a heliocentric radial velocity of +64 km/s.
The visible component is a B-type main-sequence star with a stellar classification of B9 V. It has a high rate of spin, displaying a projected rotational velocity of 149 km/s. This is giving it an oblate shape with an equatorial bulge that is an estimated 14% larger than the polar radius. 4 Sagittarii has 3.23 times the mass of the Sun and is radiating 240 times the Sun's luminosity from its photosphere at an effective temperature of 9,661 K.