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9 Sagittarii
Star in the constellation Sagittarius / From Wikipedia, the free encyclopedia
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9 Sagittarii (9 Sgr) is a massive binary star in the constellation Sagittarius. It has an apparent magnitude of 5.97. Both components are highly luminous O-type main-sequence stars.
Quick Facts Observation data Epoch J2000 Equinox J2000, Constellation ...
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Sagittarius |
Right ascension | 18h 03m 52.44501s[1] |
Declination | −24° 21′ 38.6323″[1] |
Apparent magnitude (V) | 5.97[2] |
Characteristics | |
Spectral type | O4V((f))z[3] (O3.5V((f+)) + O5–5.5V((f))[4]) |
U−B color index | −0.89[2] |
B−V color index | 0.00[2] |
Astrometry | |
Radial velocity (Rv) | 10.70[5] km/s |
Proper motion (μ) | RA: +0.539[1] mas/yr Dec.: −2.019[1] mas/yr |
Parallax (π) | 0.8001 ± 0.0728 mas[1] |
Distance | 4,100 ± 400 ly (1,200 ± 100 pc) |
Absolute magnitude (MV) | −6.20[4] |
Orbit[6] | |
Period (P) | 3,261±69 d |
Semi-major axis (a) | 4,100 R☉[7] |
Eccentricity (e) | 0.648±0.009 |
Inclination (i) | 86.5±0.5° |
Semi-amplitude (K1) (primary) | 36+4 −1 km/s |
Semi-amplitude (K2) (secondary) | 49±3 km/s |
Details[6] | |
9 Sgr A | |
Mass | 32.1±16.0 M☉ |
Radius | 10.8±1.0 R☉ |
Luminosity | 479,000 L☉ |
Surface gravity (log g) | 3.87±0.20 cgs |
Temperature | 46,000±1,000 K |
Rotational velocity (v sin i) | 102+8 −12 km/s |
9 Sgr B | |
Mass | 18.9±10.1 M☉ |
Radius | 8.9±1.2 R☉ |
Luminosity | 224,000 L☉ |
Surface gravity (log g) | 3.87±0.20 cgs |
Temperature | 42,000±1,000 K |
Rotational velocity (v sin i) | 67+6 −13 km/s |
Age | ~1 Myr |
Other designations | |
Database references | |
SIMBAD | data |
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