Nu Scorpii
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Observation data Equinox J2000.0 |
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Constellation | Scorpius |
Right ascension | 16h 11m 59.7s |
Declination | −19° 27' 39" |
Apparent magnitude (V) | combined: +4.00 AB: 4.4 + 6.9 CD: 6.5 + 7.9 |
Distance | 437 ± 65 ly (134 ± 20 pc) |
Spectral type | AB: B2IV + B2IV CD: B8V + B9VpSi |
Other designations | |
Nu Scorpii (ν Sco / ν Scorpii) is a star system in the constellation Scorpius. It also has the traditional name Jabbah, which means "forehead" in Arabic.
It is at least a quintuple star consisting of two close groups that are separated by 41". The brighter group, Nu Scorpii A and B, is split by 1.3" and composed of spectral type B2 subgiants. The fainter pair, Nu Scorpii C and D, are spectral type B8 and B9 main sequence dwarfs split by 2.4". Nu Scorpii A is itself a semi-detached spectroscopic binary, having a fainter B-type companion separated by approximately 0.0003 arcseconds.
Since it is near the ecliptic, Nu Scorpii can be occulted by the Moon and very rarely by planets. Mercury occulted it on 14 December 1821, but will not occult it again until 2 December 2031. The last occultation by Venus took place on 27 December 1852 and the next will take place on 30 December 2095. On 29 July 1808 there was an occultation by Neptune.
Nu Scorpii is the star which causes the reflection nebula cataloged as IC 4592. Reflection nebulae are actually made up of very fine dust that normally appears dark but can look quite blue when reflecting the light of energetic nearby stars.