4 Sagittarii
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Sagittarius |
Right ascension | 17h 59m 47.55132s |
Declination | −23° 48′ 58.0269″ |
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) | −18.00 km/s |
Proper motion (μ) | RA: +3.673 mas/yr Dec.: −50.327 mas/yr |
Parallax (π) | 8.3677 ± 0.4521 mas |
Distance | 390 ± 20 ly (120 ± 6 pc) |
Absolute magnitude (MV) | −0.77 |
Details | |
Mass | 3.23 M☉ |
Luminosity | 240 L☉ |
Temperature | 9,661 K |
Rotational velocity (v sin i) | 149 km/s |
Other designations | |
Database references | |
SIMBAD | data |
4 Sagittarii is a suspected astrometric binary star system in the zodiac constellation of Sagittarius, located approximately 390 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 closer to the Earth with a heliocentric radial velocity of −18 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.