Astronomy:Epsilon Normae
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Norma |
| Right ascension | 16h 27m 11.03611s[1] |
| Declination | −47° 33′ 17.2226″[1] |
| Apparent magnitude (V) | 4.47[2] |
| Characteristics | |
| Spectral type | B4 V + B4 V + B9 V[3] |
| U−B color index | −0.54[2] |
| B−V color index | −0.07[2] |
| Astrometry | |
| Radial velocity (Rv) | −12.5±2.7[4] km/s |
| Proper motion (μ) | RA: −13.68±0.27[1] mas/yr Dec.: −19.89±0.20[1] mas/yr |
| Parallax (π) | 6.15 ± 0.28[1] mas |
| Distance | 530 ± 20 ly (163 ± 7 pc) |
| Absolute magnitude (MV) | 0.06[5] |
| Orbit[6] | |
| Period (P) | 3.2617 d |
| Eccentricity (e) | 0.13 |
| Periastron epoch (T) | 2438825.9310 JD |
| Argument of periastron (ω) (secondary) | 271.5° |
| Semi-amplitude (K1) (primary) | 122.5 km/s |
| Semi-amplitude (K2) (secondary) | 132.9 km/s |
| Details | |
| Mass | 6.4±0.2[7] M☉ |
| Luminosity | 474[8] L☉ |
| Temperature | 10,888[8] K |
| Age | 50.1±14.0[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Epsilon Normae, Latinised from ε Normae, is a blue-white hued triple star[3] system in the southern constellation of Norma. It has an apparent visual magnitude of 4.47,[2] 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,[1] 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.[5]
The inner pair form a double-lined spectroscopic binary[10] system with an orbital period of 3.26 days and an eccentricity of 0.13.[6] Both stars appear to be similar B-type main-sequence stars with stellar classifications of B4 V.[3] 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.[3] The system is relatively young, with an estimated age of around 50 million years.[7]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Johnson, H. L. (1966), "UBVRIJKL Photometry of the Bright Stars", Communications of the Lunar and Planetary Laboratory 4: 99, Bibcode: 1966CoLPL...4...99J.
- ↑ 3.0 3.1 3.2 3.3 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 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, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ 5.0 5.1 Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters 38 (11): 694–706, doi:10.1134/S1063773712110035, Bibcode: 2012AstL...38..694G.
- ↑ 6.0 6.1 Pourbaix, D. et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics 424: 727–732, doi:10.1051/0004-6361:20041213, Bibcode: 2004A&A...424..727P.
- ↑ 7.0 7.1 7.2 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, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ 8.0 8.1 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ "eps Nor". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=eps+Nor.
- ↑ 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, doi:10.1111/j.1365-2966.2012.21317.x, Bibcode: 2012MNRAS.424.1925C.
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