Lambda Normae

λ Normae, Latinised as Lambda Normae, is a binary star[2] 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.[1] 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.[1]

Lambda Normae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Norma
Right ascension 16h 19m 17.64661s
Declination −42° 40′ 26.3014″
Apparent magnitude (V) 5.44[1] (5.83 + 6.86)[2]
Characteristics
Spectral type A0V + A3V
B−V color index 0.099±0.004[1]
Astrometry
Radial velocity (Rv)−15.0±3.7[1] km/s
Proper motion (μ) RA: +7.59 mas/yr
Dec.: −13.30 mas/yr
Parallax (π)9.35 ± 0.76[3] mas
Distance350 ± 30 ly
(107 ± 9 pc)
Absolute magnitude (MV)0.31[1]
Orbit[2]
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[1] 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.[2] 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. 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.
  2. "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Retrieved 16 May 2017.
  3. 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.
  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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