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Epsilon Normae, Latinised from ε Normae, is a blue-white hued triple star system in the southern constellation of Norma. It has an apparent visual magnitude of 4.47, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 6.15 mas as seen from Earth, the system is located around 530 light years distant from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.21 due to interstellar dust.

The inner pair form a double-lined spectroscopic binary system with an orbital period of 3.26 days and an eccentricity of 0.13. Both stars appear to be similar B-type main-sequence stars with stellar classifications of B4 V. The third component has an angular separation of 22.8 arc seconds from the inner pair, and most likely is a smaller B-type main sequence star of spectral type B9V. The system is relatively young, with an estimated age of around 50 million years.

References

1. ^ 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.
2. ^ Johnson, H. L. (1966), "UBVRIJKL Photometry of the Bright Stars", Communications of the Lunar and Planetary Laboratory, 4: 99, Bibcode:1966CoLPL...4...99J.
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, S2CID 14878976.
4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
5. ^ Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035, S2CID 119108982.
6. ^ Pourbaix, D.; et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics, 424: 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
7. ^ Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
8. ^ McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
9. "eps Nor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-12.{{cite web}}: CS1 maint: postscript (link)
10. Chini, R.; et al. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society, 424 (3): 1925, arXiv:1205.5238, Bibcode:2012MNRAS.424.1925C, doi:10.1111/j.1365-2966.2012.21317.x, S2CID 119120749.

v t e Constellation of Norma
List of stars in Norma
Stars	Bayer γ γ δ ε ζ η θ ι ι κ λ μ Variable R S T RT RZ IM QU QV QX V378 HD 142415 143183 143361 148156 148937 330075 Other 1E 161348-5055 2M1540 2XMM J160050.7–514245 (Apep) SCR J1546−5534 SGR J1550−5418 XTE J1550–564
Exoplanets HD 142415 b HD 143361 b HD 148156 b HD 330075 b
Star clusters NGC 5925 NGC 5999 NGC 6005 NGC 6031 NGC 6067 NGC 6087 NGC 6115 NGC 6134 NGC 6152 NGC 6167 NGC 6169
Nebulae Mz 1 Mz 3 RCW 103 SDC 335.579-0.292 Shapley 1
Galaxy clusters Norma Cluster
Category

• B-type main-sequence stars
• Triple star systems
• Norma (constellation)
• Bayer objects
• Durchmusterung objects
• Henry Draper Catalogue objects
• Hipparcos objects
• Bright Star Catalogue objects