Epsilon Normae
  | |
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Norma |
| A | |
| Right ascension | 16h 27m 11.04161s |
| Declination | −47° 33′ 17.2571″ |
| Apparent magnitude (V) | 4.47 |
| B | |
| Right ascension | 16h 27m 10.06643s |
| Declination | −47° 32′ 56.6763″ |
| Apparent magnitude (V) | 6.13 |
| Characteristics | |
| Spectral type | B4 V + B4 V + B9 V |
| U−B color index | −0.54 |
| B−V color index | −0.07 |
| Astrometry | |
| A | |
| Radial velocity (Rv) | −12.5±2.7 km/s |
| Proper motion (μ) | RA: −12.049 mas/yr Dec.: −20.278 mas/yr |
| Parallax (π) | 5.2390±0.1514 mas |
| Distance | 620 ± 20 ly (191 ± 6 pc) |
| Absolute magnitude (MV) | +0.06 |
| B | |
| Radial velocity (Rv) | −6.67±0.83 km/s |
| Proper motion (μ) | RA: −10.393 mas/yr Dec.: −20.277 mas/yr |
| Parallax (π) | 5.4467±0.0299 mas |
| Distance | 599 ± 3 ly (184 ± 1 pc) |
| Orbit | |
| Primary | Aa |
| Secondary | Ab |
| 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 | |
| Aa | |
| Mass | 7.7 M☉ |
| Ab | |
| Mass | 4.5 M☉ |
| B | |
| Mass | 2.3 M☉ |
| Radius | 2.4 R☉ |
| Luminosity | 74 L☉ |
| Surface gravity (log g) | 4.00 cgs |
| Temperature | 11,104 K |
| Other designations | |
| ε Nor, WDS J16272-4733 | |
| A: Yaqana, CD−47°10765, HD 147971, HIP 80582, HR 6115, SAO 226773 | |
| B: CD−47°10764, HD 147970, HIP 80579, SAO 226772 | |
| Database references | |
| SIMBAD | A |
| B | |
Epsilon Normae, Latinised from ε Normae, also named Yaqana, 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 5.24 mas as seen from Earth, the system is located around 620 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, at an angular separation of 22.8 arc seconds from the inner pair, is HD 147970. It is most likely is a smaller B-type main sequence star of spectral type B9V.
Yaqana, the llama, is an Inca dark constellation in an area between Centaurus and Scorpius, including Norma. Near it is a smaller dark constellation called Uñallamacha, the cria (baby llama). The IAU Working Group on Star Names adopted the name Yaqana for ε Normae Aa on 18 June 2026.
References
- 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- 1 2 3 4 Johnson, H. L. (1966), "UBVRIJKL Photometry of the Bright Stars", Communications of the Lunar and Planetary Laboratory, 4: 99, Bibcode:1966CoLPL...4...99J.
- 1 2 3 4 5 6 7 8 9 10 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ↑ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355. Bibcode:2000A&A...355L..27H.
- 1 2 3 4 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.
- ↑ 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.
- 1 2 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.
- 1 2 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.
- 1 2 3 Tokovinin, Andrei (2018). "The Updated Multiple Star Catalog". The Astrophysical Journal Supplement Series. 235 (1): 6. arXiv:1712.04750. Bibcode:2018ApJS..235....6T. doi:10.3847/1538-4365/aaa1a5.
- 1 2 "eps Nor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-12.
- ↑ "HD 147970". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2025-05-28.
- 1 2 "IAU Catalog of Star Names". Retrieved 21 June 2026.
- ↑ 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.
- ↑ Azkarrula, Youla; Hoffmann, Susanne M; Gullberg, Steven R. "Yaqana". All Skies Encyclopaedia. IAU Working Group on Star Names. Retrieved 21 June 2026.
