Epoch J2000.0 Equinox J2000.0
|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
It is at least a quintuple star, probably a septuple, consisting of two close groups that are separated by 41 arcseconds. 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 0.3 mas.
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.
In Chinese astronomy, Nu Scorpii is called 鍵閉, Pinyin: Jiànbì, meaning Door Bolt, because this star is marking itself and stand alone in Door Bolt asterism, Room mansion (see : Chinese constellation). 鍵閉 (Jiànbì), westernized into Keen Pi, but the name Keen Pi was designated for the formation of λ Sco (Shaula) and υ Sco (Lesath) by R.H. Allen and the meaning is "the Two Parts of a Lock." 
- AR Cassiopeiae (IH Cas), another multiple star considered to have a multiplicity of 7
|This subgiant-star-related article is a stub. You can help Wikipedia by expanding it.|
|This binary or multiple star system–related article is a stub. You can help Wikipedia by expanding it.|