Epsilon Normae
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Norma |
| A | |
| Right ascension | 16h 27m 11.03611s |
| Declination | −47° 33′ 17.2226″ |
| 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: −13.68±0.27 mas/yr Dec.: −19.89±0.20 mas/yr |
| Parallax (π) | 6.15±0.28 mas |
| Distance | 530 ± 20 ly (163 ± 7 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 |
| Companion | 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, CD−47°10765, HD 147971, HIP 80582, HR 6115, SAO 226773, WDS J16272-4733A | |
| B: HD 147970, HIP 80579 | |
| Database references | |
| SIMBAD | data |
| B | |
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, 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.