Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Sagittarius |
Right ascension | 18h 21m 19.548s[1] |
Declination | −16° 22′ 16.0572″[1] |
Apparent magnitude (V) | 8.30–8.41[2] |
Characteristics | |
Spectral type | B6Ia+[3] (B2—B8[4]) May be B60 due to hypergiant designation |
U−B color index | +0.37[5] |
B−V color index | +1.41[5] |
J−K color index | 0.599 |
Variable type | α Cygni[6] |
Astrometry | |
Radial velocity (Rv) | −4.00[7] km/s |
Proper motion (μ) | RA: −0.71±1.20[1] mas/yr Dec.: +0.01±0.74[1] mas/yr |
Parallax (π) | 0.6212 ± 0.0640 mas[8] |
Distance | approx. 5,300 ly (approx. 1,600 pc) |
Absolute magnitude (MV) | −8.39[4] |
Details[4] | |
Radius | 105 R☉ |
Luminosity | 380,000 L☉ |
Surface gravity (log g) | 1.74 cgs |
Temperature | 14,000 K |
Rotational velocity (v sin i) | 60 km/s |
Other designations | |
Database references | |
SIMBAD | data |
HD 168625 (V4030 Sagittarii) is a blue hypergiant star and candidate luminous blue variable located in the constellation of Sagittarius easy to see with amateur telescopes. It forms a visual pair with the also blue hypergiant (and luminous blue variable) HD 168607 and is located to the south-east of M17, the Omega Nebula.
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