Lambda Normae

λ Normae, Latinised as Lambda Normae, is a binary star[3] system in the southern constellation of Norma, located near the northern constellation boundary with Scorpius. It is visible to the naked eye as a dim, white-hued point of light that shines with a combined apparent visual magnitude of 5.44.[2] The system is located approximately 350 light years distant from the Sun based on parallax, but is drifting closer with a radial velocity of about −15 km/s.[2]

Lambda Normae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Norma
Right ascension 16h 19m 17.64660s[1]
Declination −42° 40′ 26.3014″[1]
Apparent magnitude (V) 5.44[2] (5.83 + 6.86)[3]
Characteristics
Spectral type A0V + A3V
B−V color index 0.099±0.004[2]
Astrometry
Radial velocity (Rv)−15.0±3.7[2] km/s
Proper motion (μ) RA: +7.59[1] mas/yr
Dec.: −13.30[1] mas/yr
Parallax (π)9.35 ± 0.76 mas[1]
Distance350 ± 30 ly
(107 ± 9 pc)
Absolute magnitude (MV)0.31[2]
Orbit[3]
Period (P)67.50 yr
Semi-major axis (a)0.293″
Eccentricity (e)0.788
Inclination (i)45.8°
Longitude of the node (Ω)215.2°
Periastron epoch (T)2049.59 B
Argument of periastron (ω)
(secondary)		82.5°
Details
Luminosity64[2] L☉
λ Nor A
Mass2.53–2.57[4] M☉
λ Nor B
Mass2.00–2.13[4] M☉
Other designations
λ Nor, CD−42°11188, HD 146667, HIP 79963, HR 6071, SAO 226650, WDS J16193-4240[5]
Database references
SIMBADdata

The pair have an orbital period of 67.5 years with a high eccentricity of 0.788.[3] Both components are A-type main-sequence stars that are generating energy through core hydrogen fusion. The primary component has a visual magnitude of 5.83, and is of class A0V. The fainter secondary is class A3V with a magnitude 6.86.[6]

References
  1. van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction". Astronomy and Astrophysics. 474 (2): 653–64. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  2. 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, S2CID 119257644.
  3. "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 16 May 2017.
  4. Cvetkovic, Z.; Ninkovic, S. (2010), "On the Component Masses of Visual Binaries", Serbian Astronomical Journal, 180 (180): 71–80, Bibcode:2010SerAJ.180...71C, doi:10.2298/SAJ1080071C
  5. "lam Nor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 31 March 2015.
  6. last, O. Yu.; Tamazian, V. S.; Docobo, J. A.; Chulkov, D. A. (2012). "Dynamical masses of a selected sample of orbital binaries". Astronomy & Astrophysics. 546: 5. Bibcode:2012A&A...546A..69M. doi:10.1051/0004-6361/201219774. A69.
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