Nu Scorpii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Scorpius[1] |
| ν Sco A | |
| Right ascension | 16h 11m 59.740s[2] |
| Declination | −19° 27′ 38.33″[2] |
| Apparent magnitude (V) | 4.349[2] |
| ν Sco B | |
| Right ascension | 16h 11m 59.746s[3] |
| Declination | −19° 27′ 36.94″[3] |
| Apparent magnitude (V) | 6.60[3] |
| ν Sco C | |
| Right ascension | 16h 11m 58.541s[4] |
| Declination | −19° 27′ 00.63″[4] |
| Apparent magnitude (V) | 6.60[3] |
| ν Sco D | |
| Right ascension | 16h 11m 58.541s[5] |
| Declination | −19° 27′ 00.63″[5] |
| Apparent magnitude (V) | 7.23[3] |
| Characteristics | |
| ν Sco AB | |
| Spectral type | B3V (A)[6] |
| U−B color index | −0.63[7] |
| B−V color index | +0.05[7] |
| ν Sco CD | |
| Spectral type | B8V + B9VpSi[8] |
| U−B color index | −0.37[7] |
| B−V color index | +0.13[7] |
| Astrometry | |
| ν Sco AB | |
| Radial velocity (Rv) | +2.4±5[9] km/s |
| Proper motion (μ) | RA: −7.65[10] mas/yr Dec.: −23.71[10] mas/yr |
| Parallax (π) | 6.88±0.76 mas[10] |
| Distance | approx. 470 ly (approx. 150 pc) |
| Absolute magnitude (MV) | −1.78[1] |
| ν Sco C | |
| Radial velocity (Rv) | −9.72±0.64[11] km/s |
| Proper motion (μ) | RA: −11.853[4] mas/yr Dec.: −24.920[4] mas/yr |
| Parallax (π) | 7.2608±0.0348 mas[4] |
| Distance | 449 ± 2 ly (137.7 ± 0.7 pc) |
| Absolute magnitude (MV) | +0.754[12] |
| ν Sco D | |
| Radial velocity (Rv) | −3.0[13] km/s |
| Proper motion (μ) | RA: −7.099[5] mas/yr Dec.: −22.792[5] mas/yr |
| Parallax (π) | 7.1732±0.01399 mas[5] |
| Distance | 454.7 ± 0.9 ly (139.4 ± 0.3 pc) |
| Orbit[14] | |
| Primary | ν Sco Aa |
| Name | ν Sco Ab |
| Period (P) | 5.55206±0.00003 d |
| Eccentricity (e) | 0.11±0.05 |
| Periastron epoch (T) | 2442185.555±0.349 |
| Argument of periastron (ω) (secondary) | 267±23° |
| Semi-amplitude (K1) (primary) | 26.5±1.3 km/s |
| Orbit[6] | |
| Primary | ν Sco Aab |
| Name | ν Sco Ac |
| Period (P) | 10.0611 yr |
| Semi-major axis (a) | 0.073 AU |
| Eccentricity (e) | 0.92 |
| Inclination (i) | 89.7° |
| Longitude of the node (Ω) | 346.4° |
| Periastron epoch (T) | 2014.987 |
| Argument of periastron (ω) (secondary) | 118.9° |
| Orbit[6] | |
| Primary | ν Sco A |
| Name | ν Sco B |
| Period (P) | 500 yr |
| Semi-major axis (a) | 1.126 AU |
| Eccentricity (e) | 0.5 |
| Inclination (i) | 91.2° |
| Longitude of the node (Ω) | 0.9° |
| Periastron epoch (T) | 1672 |
| Argument of periastron (ω) (secondary) | 125.0° |
| Details | |
| Aa | |
| Mass | 5.1+0.3 −0.2[15] M☉ |
| Radius | 6.52+0.24 −0.23[15] R☉ |
| Luminosity | 1,260+250 −160[15] L☉ |
| Surface gravity (log g) | 3.48±0.04[15] cgs |
| Temperature | 13,400+900 −550[15] K |
| Metallicity [Fe/H] | 0.58[15] dex |
| Ab | |
| Mass | 2.28[6] M☉ |
| Ac | |
| Mass | 2.46[6] M☉ |
| B | |
| Mass | 3.79[6] M☉ |
| C | |
| Mass | 2.46[6] M☉ |
| Radius | 2.4[4] R☉ |
| Luminosity | 155[4] L☉ |
| Surface gravity (log g) | 4.25[4] cgs |
| Temperature | 13,252[4] K |
| Metallicity [Fe/H] | 0.40[4] dex |
| Da | |
| Mass | 1.96[6] M☉ |
| Other designations | |
| Jabbah, ν Sco, 14 Sco, ADS 9951, CCDM J16120-1928[16] | |
| ν Sco AB: BD−19°4333, HD 145502, HIP 79374, HR 6027, SAO 159764[17][18] | |
| ν Sco CD: BD−19°4332, HD 145501, HR 6026, SAO 159763[19][20] | |
| Database references | |
| SIMBAD | ν Sco |
| ν Sco A | |
| ν Sco B | |
| ν Sco C | |
| ν Sco D | |
Nu Scorpii (ν Scorpii, abbreviated Nu Sco, ν Sco) is a multiple star system in the constellation of Scorpius. It is most likely a septuple star system,[6] consisting of two close groups (designated Nu Scorpii AB and CD) that are separated by 41 arcseconds.[6] Based on parallax measurements,[10] it is approximately 470 light-years from the Sun.
The component Nu Scorpii Aa is formally named Jabbah /ˈdʒæbə/.[21]
Location

Nu Scorpii is the system that causes the reflection nebula cataloged as IC 4592 and known as the Blue Horsehead nebula. 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.[22]
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.
Nomenclature
ν Scorpii (Latinised to Nu Scorpii) is the system's Bayer designation. The designations of its two constituent groups as Nu Scorpii AB and CD; of the component Nu Scorpii Aa, and of other components similarly lettered, derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[23]

Nu Scorpii bore the traditional name Jabbah, possibly from the Arabic Iklīl al Jabhah (إكليل الجبهة 'the crown of the forehead').[24][25] In 2016, the IAU organized a Working Group on Star Names (WGSN)[26] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[27] It approved the name Jabbah for the component Nu Scorpii Aa on 30 June 2017 and it is now so included in the List of IAU-approved Star Names.[21]
In Chinese astronomy, Nu Scorpii is called 鍵閉, Pinyin: Jiànbì, meaning Door Bolt, because it is marking itself and standing alone in the Door Bolt asterism, Room mansion (see : Chinese constellations).[28] 鍵閉 (Jiànbì), westernized into Keen Pi, but that name (meaning "the Two Parts of a Lock") was ascribed to the pair Lambda Scorpii (Shaula) and Upsilon Scorpii (Lesath) by R.H. Allen.[25]
Multiplicity
| Aa | |||||||||||||||||
| Period = 5.55d a = 1.06 mas | |||||||||||||||||
| Ab | |||||||||||||||||
| Period = 5.7y a = 63 mas | |||||||||||||||||
| Ac | |||||||||||||||||
| 1.3″ separation | |||||||||||||||||
| B | |||||||||||||||||
| 41.1″ separation | |||||||||||||||||
| C | |||||||||||||||||
| 2″ separation | |||||||||||||||||
| Da | |||||||||||||||||
| Orbit unknown | |||||||||||||||||
| Db | |||||||||||||||||
Hierarchy of orbits in the ν Scorpii system

Nu Scorpii is a septuple star system.[6] It is one of only two such 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.[19] Nu Scorpii AB and CD cannot be resolved using the naked eye, but can be resolved using a telescope.[29]
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.
Nu Scorpii A is itself a triple star system. The inner pair 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.[14] 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.[6]
The outer star, Nu Scorpii Ac, is 63 milliarcseconds away from the inner pair and it has an apparent magnitude of 6.62.[6]
Nu Scorpii B
Nu Scorpii B is part of the Nu Scorpii AB sub-system and orbits the three Nu Scorpii A stars. 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. It has an apparent magnitude of 5.40, but its spectral type is unknown.[6]
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 main sequence star with a spectral type of B8V. 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.[6]
Nu Scorpii D, with an apparent magnitude of 7.39, is the faintest component of the Nu Scorpii system and has a spectral class of B9V. 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 late B star, similar to Nu Scorpii C, but very little is known about Nu Scorpii Db.[30]
References
- ^ a b Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
- ^ a b c Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
- ^ a b c d e Fabricius, C.; Høg, E.; Makarov, V. V.; Mason, B. D.; Wycoff, G. L.; Urban, S. E. (2002). "The Tycho double star catalogue". Astronomy and Astrophysics. 384: 180–189. Bibcode:2002A&A...384..180F. doi:10.1051/0004-6361:20011822.
- ^ a b c d e f g h i j Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e f g h i j k l m n o Tokovinin, Andrei (March 2018). "The Updated Multiple Star Catalog". The Astrophysical Journal Supplement Series. 235 (1): 6. arXiv:1712.04750. Bibcode:2018ApJS..235....6T. doi:10.3847/1538-4365/aaa1a5. ISSN 0067-0049. S2CID 119047709.
- ^ a b c d Nicolet, B. (1964). "Catalogue of homogeneous data in the UBV photoelectric photometric system". Astronomy and Astrophysics Supplement Series. 34: 1–49. Bibcode:1978A&AS...34....1N. Color indices accessed using SIMBAD.
- ^ Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
- ^ Evans, D. S. (2006). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications. 30: 57. Bibcode:1967IAUS...30...57E.
- ^ a b c d van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ Miret-Roig, N.; Galli, P. A. B.; Olivares, J.; Bouy, H.; Alves, J.; Barrado, D. (2022). "The star formation history of Upper Scorpius and Ophiuchus. A 7D picture: Positions, kinematics, and dynamical traceback ages". Astronomy and Astrophysics. 667. arXiv:2209.12938. Bibcode:2022A&A...667A.163M. doi:10.1051/0004-6361/202244709.
- ^ Freund, S.; Robrade, J.; Schneider, P. C.; Schmitt, J. H. M. M. (2018). "The stellar content of the XMM-Newton slew survey". Astronomy and Astrophysics. 614: A125. arXiv:1712.07410. Bibcode:2018A&A...614A.125F. doi:10.1051/0004-6361/201732009.
- ^ Duflot, M.; Figon, P.; Meyssonnier, N. (1995). "Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue". Astronomy and Astrophysics Supplement Series. 114: 269. Bibcode:1995A&AS..114..269D.
- ^ a b Levato, H.; Malaroda, S.; Morrell, N.; Solivella, G. (1987). "Stellar multiplicity in the Scorpius-Centaurus association". Astrophysical Journal Supplement Series. 64: 487–503. Bibcode:1987ApJS...64..487L. doi:10.1086/191204.
- ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ "nu Sco". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2026-04-01.
- ^ "nu Sco A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 1 April 2026.
- ^ "nu Sco B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 1 April 2026.
- ^ a b "nu Sco C". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 1 April 2026.
- ^ "nu Sco D". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 1 April 2026.
- ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
- ^ "WISE - Multimedia Gallery: IC 4592". WISE: Wide-Field Infrared Survey Explorer. 22 November 2011. Retrieved 24 February 2017.
- ^ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
- ^ Kaler, Jim. "Jabbah". Retrieved 2017-01-29.
- ^ a b Allen, Richard Hinckley. "Star Names — Their Lore and Meaning: Scorpio". Retrieved 2017-01-29.
- ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
- ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 8 日 Archived 2020-01-13 at the Wayback Machine
- ^ "* nu. Sco". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 24 February 2017.
- ^ Andersen, J.; Nordstrom, B. (1983). "Radial velocities of bright southern stars. I - 139 B-type HR and FK stars". Astronomy and Astrophysics Supplement Series. 52: 471–482. Bibcode:1983A&AS...52..471A.
