Nu1 Sagittarii

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Nu¹ Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
Cercle rouge 100%.svg
Location of ν¹ Sagittarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 18h 54m 10.17695s[1]
Declination −22° 44′ 41.4247″[1]
Apparent magnitude (V) +4.86[2]
Spectral type G2/K1 Ib/II + B9.2p[3]
U−B color index +1.34[2]
B−V color index +1.43[2]
Proper motion (μ) RA: +2.59[1] mas/yr
Dec.: −8.41[1] mas/yr
Parallax (π)2.90 ± 0.30[1] mas
Distanceapprox. 1,100 ly
(approx. 340 pc)
Absolute magnitude (MV)−3.91[4]
Other designations
Ainalrami, ν¹ Sgr, 32 Sgr, BD−22° 4907, HD 174974, HIP 92761, HR 7116, SAO 187426, WDS J18542-2245[5]
Database references

Nu¹ Sagittarii (ν¹ Sagittarii, abbreviated Nu¹ Sgr, ν¹ Sgr) is a triple star system[6] lying approximately 1,100 light-years from Earth. Its three components are designated Nu¹ Sagittarii A (also named Ainalrami),[7] B and C.[8] A and B themselves form a spectroscopic binary.[6]


ν¹ Sagittarii (Latinised to Nu¹ Sagittarii) is the system's Bayer designation.

Nu¹ and Nu² Sagittarii (together designated Nu Sagittarii) bore the traditional name Ain al Rami, which is from the Arabic عين الرامي cain ar-rāmī meaning 'eye of the archer'.[9] In 2016, the IAU organized a Working Group on Star Names (WGSN)[10] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[11] It approved the name Ainalrami for the component Nu¹ Sagittarii A on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[7]

Nu¹ and Nu² Sagittarii, together with Tau Sagittarii, Psi Sagittarii, Omega Sagittarii, 60 Sagittarii and Zeta Sagittarii were Al Udḥiyy, the Ostrich's Nest.[9]


Nu¹ Sagittarii A is a spectral type K1 bright giant which has an apparent magnitude of +4.86. It is a microvariable with a frequency of 0.43398 cycles per day and an amplitude of 0.0078 magnitude.[12] In 1982 it was found to have a hotter companion, Nu¹ Sagittarii B, a rapidly rotating B9 type star.[13] The pair orbit with a period of around 370 days.[6] A magnitude +11.2 companion, component C,[8] is orbiting further out at an angular separation of 2.5 arcseconds from the primary.[6]


  1. 1.0 1.1 1.2 1.3 1.4 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.
  2. 2.0 2.1 2.2 Lutz, T. E.; Lutz, J. H. (June 1977), "Spectral classification and UBV photometry of bright visual double stars", Astronomical Journal 82: 431–434, Bibcode 1977AJ.....82..431L, doi:10.1086/112066.
  3. Parsons, Sidney B.; Ake, Thomas B. (1998), "Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample", The Astrophysical Journal Supplement Series 119: 83, Bibcode 1998ApJS..119...83P, doi:10.1086/313152.
  4. Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics 430: 303–311, arXiv:astro-ph/0409683, Bibcode 2005A&A...430..303C, doi:10.1051/0004-6361:20041440.
  5. Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  6. 6.0 6.1 6.2 6.3 Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, arXiv:0806.2878, Bibcode 2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  7. 7.0 7.1 Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  8. 8.0 8.1 Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  9. 9.0 9.1 Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  10. Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  11. Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  12. Koen, Chris; Eyer, Laurent (2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society 331: 45, arXiv:astro-ph/0112194, Bibcode 2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x.
  13. Kondo, Y. et al. (August 1982), "The early-type component in ν¹ Sagittarii", Publications of the Astronomical Society of the Pacific 94: 647–649, Bibcode 1982PASP...94..647K, doi:10.1086/131037.

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