Primary ν Sco Aa | Companion ν Sco Ab | |
Nu Scorpii (ν Sco, 14 Scorpii) also known as Jabbah is a star system in the constellation Scorpius.
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It is at least a quintuple star, probably a septuple, consisting of two close groups that are separated by 41 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.
Nomenclature
Nu Scorpii bears the traditional name Jabbah.
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." Instead Allen notes the name Jabbah, possibly from Iklīl al Jabhah.
Multiplicity
Nu Scorpii is a septuple star system. It is one of only two known systems, the other being AR Cassiopeiae. Higher-multiplicity star systems are uncommon because they are less stable than their simpler counterparts, and often decay into smaller systems.
Nu Scorpii is split into two groups, Nu Scorpii AB and Nu Scorpii CD. Nu Scorpii CD is located 41 arcseconds away from Nu Scorpii A, and is also known as HR 6026.
Nu Scorpii A
Nu Scorpii A is the brightest member of the system. It has an apparent magnitude from 4.35, meaning that it can be seen with the naked eye. However, Nu Scorpii AB and CD cannot be resolved using the naked eye, but it can be resolved using a telescope.
Nu Scorpii A is itself a triple star system. The main component of Nu Scorpii A is known as Nu Scorpii Aab, and it is a single-lined spectroscopic binary. Its components cannot be resolved but the stars' movements cause periodic Doppler shifts in their spectra. "Single-lined" means that light from only one of the stars can be detected. The pair has an orbital period of 5.5521 days and an eccentricity of 0.11, and an estimated separation of about 1.057 milliarcseconds. The brighter component, Nu Scorpii Aa, has a spectral type of B3V implying a B-type main-sequence star. The fainter component, Nu Scorpii Ab, is thought to have an apparent magnitude of 6.90.
Nu Scorpii Ac is the third component of the Nu Scorpii A subsystem. 63 milliarcseconds away, it has an apparent magnitude of 6.62.
Nu Scorpii B
Nu Scorpii B is part of the Nu Scorpii AB sub-system and orbits Nu Scorpii A. It has an apparent magnitude of 5.40, but its spectral type is unknown. Nu Scorpii A and B are separated by 1.305 arcseconds; this translates to an orbital period of over 452 years, so no orbital motion has been detected.
Nu Scorpii CD
Nu Scorpii CD is also a triple star system. The primary component of the system, Nu Scorpii C, is a late B-type giant with a spectral type of B9III. With an apparent magnitude of 6.90, it outshines its fainter companion, Nu Scorpii D, which only has an apparent magnitude of 7.39. The two are separated by about 2 arcseconds.
Nu Scorpii D, with an apparent magnitude of 7.39, is the faintest component of the Nu Scorpii system. It is one of a class of chemically peculiar stars known as Ap/Bp stars; in particular, it has strong silicon emission lines. It too is likely also another spectroscopic binary: Nu Scorpii Da is another B9III-type star, similar to Nu Scorpii C, but very little is known about Nu Scorpii Db.