Epsilon Normae

Epsilon Normae
Observation data
Epoch J2000.0      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 mas[1]
Distance530 ± 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
Mass6.4±0.2[7] M☉
Luminosity474[8] L☉
Temperature10,888[8] K
Age50.1±14.0[7] Myr
Other designations
ε Nor, CD−47° 10765, HD 147971, HIP 80582, HR 6115, SAO 226773, WDS J16272-4733A[9]
Database references
SIMBADdata

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]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Pourbaix2004 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference McDonald2012 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference chini2012 was invoked but never defined (see the help page).