  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius[1] |
| Right ascension | 17h 59m 47.55646s[2] |
| Declination | −23° 48′ 58.0130″[2] |
| Apparent magnitude (V) | 4.74[1] |
| Characteristics | |
| Spectral type | B9V[3] |
| U−Bcolor index | −0.03[4] |
| B−Vcolor index | -0.05[4] |
| Astrometry | |
| Radial velocity (Rv) | 64.33±1.32[2] km/s |
| Proper motion (μ) | RA: −0.900mas/yr[2] Dec.: −51.149mas/yr[2] |
| Parallax (π) | 7.9879±0.3689 mas[2] |
| Distance | 410 ± 20 ly (125 ± 6 pc) |
| Absolute magnitude (MV) | −0.77[1] |
| Details | |
| Mass | 3.23[5] M☉ |
| Radius | 5.53[5][a] R☉ |
| Luminosity | 240[5] L☉ |
| Temperature | 9,661[5] K |
| Rotational velocity (v sin i) | 149[5] km/s |
| Other designations | |
| 4 Sgr,CD−23°13731,FK5 3430,GC 24483,HD 163955,HIP 88116,HR 6700,SAO 186061,GSC 06841-01403[6] | |
| Database references | |
| SIMBAD | data |
4 Sagittarii is a suspectedastrometric binary[7]star system in thezodiacconstellation ofSagittarius, located approximately 410 light-years away based on parallax.[2] It is visible to the naked eye as a faint, blue-white hued star with anapparent visual magnitude of 4.74.[1] The system is moving away from the Earth with a heliocentricradial velocity of +64 km/s.[2]
The visible component is aB-type main-sequence star with astellar classification of B9 V.[3] It has a high rate of spin, displaying aprojected rotational velocity of 149 km/s.[5] This is giving it anoblate shape with anequatorial bulge that is an estimated 14% larger than the polar radius.[8] 4 Sagittarii has 3.23 times themass of the Sun and is radiating 240 times theSun's luminosity from itsphotosphere at aneffective temperature of 9,661 K.[5]
