HD 5980

HD 5980

X-ray image by Chandra Observatory
Observation data
Epoch J2000      Equinox J2000
Constellation Tucana
Right ascension 00h 59m 26.569s[1]
Declination −72° 09′ 53.91″[1]
Apparent magnitude (V) 8.8 - 11.9[2]
Characteristics
Spectral type LBV + WN4 + OI[3]
U−B color index −0.99[4]
B−V color index −0.18[5]
Variable type LBV[6] and EA[3]
Astrometry
Radial velocity (Rv)−20[7] km/s
Proper motion (μ) RA: −3.5[1] mas/yr
Dec.: −2.4[1] mas/yr
Distance200,000 ly
(64,000[6] pc)
Absolute magnitude (MV)−8.1 (−7.1/−6.8/−6.7)[8]
Orbit[7]
PrimaryHD 5980 A
CompanionHD 5980 B
Period (P)19.2656±0.0009 d
Semi-major axis (a)151±4 R☉
Eccentricity (e)0.27±0.02
Inclination (i)86°
Periastron epoch (T)2,451,424.97±0.25
Argument of periastron (ω)
(primary)		134±4°
Semi-amplitude (K1)
(primary)		214±6 km/s
Semi-amplitude (K2)
(secondary)		200±6 km/s
Orbit[7]
PrimaryHD 5980 C
Period (P)96.56±0.01 d
Eccentricity (e)0.815
Periastron epoch (T)2451183.40±0.22
Argument of periastron (ω)
(primary)		252±3.3[7]°
Semi-amplitude (K2)
(secondary)		81±4 km/s
Details
A
Mass61[8] M☉
Radius24[8] (21[3] – 280[9]) R☉
Luminosity2,200,000[8] (2,000,000[10] – 10,000,000[9]) L☉
Temperature45,000[8] (21,000 – 53,000[3]) K
Metallicity [Fe/H]−1.0[6] dex
Rotational velocity (v sin i)250[11] km/s
B
Mass66[8] M☉
Radius22[8] R☉
Luminosity1,800,000[8] L☉
Temperature45,000[8] K
Metallicity [Fe/H]−1.0[6] dex
Rotational velocity (v sin i)<400[8] km/s
Age2.6[8] Myr
C
Mass34[8] M☉
Radius24[8] R☉
Luminosity708,000[8] L☉
Temperature34,000[8] K
Metallicity [Fe/H]≅ −0.7[6] dex
Rotational velocity (v sin i)120[8] km/s
Age3.1[7] Myr
Other designations
HD 5980, RMC 14, Sk 78, AB 5, SMC WR5, AAVSO 0056-72
Database references
SIMBADdata

HD 5980 is a multiple star system on the outskirts of NGC 346 in the Small Magellanic Cloud (SMC)[12] and is one of the brightest stars in the SMC.

HD 5980 has at least three components among the most luminous stars known: the unusual primary has a Wolf–Rayet spectrum and has produced a luminous blue variable (LBV) outburst; the secondary, also a Wolf–Rayet star, forms an eclipsing spectroscopic binary with the primary star; and a more distant O-type supergiant is also likely to be a binary.

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  6. ^ a b c d e Cite error: The named reference triple was invoked but never defined (see the help page).
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  11. ^ Cite error: The named reference gloria was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Nazé2002 was invoked but never defined (see the help page).