Mu Normae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Mu Normae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Norma
Right ascension 16h 34m 05.0207s
Declination −44° 02′ 43.133″
Apparent magnitude (V) 4.914
Spectral type O9.7Iab[1]
Apparent magnitude (U) 4.14
Apparent magnitude (B) 4.951
Apparent magnitude (J) 4.912
Apparent magnitude (H) 4.679
Apparent magnitude (K) 4.612
U−B color index -0.811
B−V color index +0.0369
Variable type Suspected Alpha Cygni
Radial velocity (Rv) +8.6 km/s
Proper motion (μ) RA: 0.52 mas/yr
Dec.: -2.53 mas/yr
Parallax (π) 0.70 ± 0.73 mas
Distance 1,000[2] pc
Absolute magnitude (MV) -6.45[1]
Mass 30 M
Radius 25[1] R
Luminosity 210,000 L
Luminosity (visual, LV) 339,000[1] L
Surface gravity (log g) 2.91[1] cgs
Temperature 28,000[1] K
Rotational velocity (v sin i) 57[1] km/s
Age ~4 million years
Other designations
Database references

Mu Normae is a blue supergiant star in the constellation Norma. Though it has an apparent magnitude of only 4.914, its absolute visual magnitude -5.86 and a bolometric luminosity of 210,000 times that of the Sun. This star is comparable to Epsilon Orionis (Alnilam) in that they are both of class B0 and are supergiants, but this star is less massive at a probable mass of 30 solar masses. Both stars are also suspected of being Alpha Cygni variables which are named after the also similar star Deneb. Being a blue supergiant, it is destined to become a red supergiant in a few million years and eventually a type-II supernova.


  1. ^ a b c d e f g Lefever, K.; Puls, J.; Aerts, C. (2007). "Statistical properties of a sample of periodically variable B-type supergiants". Astronomy and Astrophysics 463 (3): 1093. doi:10.1051/0004-6361:20066038.  edit
  2. ^ Fullerton, A. W.; Massa, D. L.; Prinja, R. K. (2006). "The Discordance of Mass‐Loss Estimates for Galactic O‐Type Stars". The Astrophysical Journal 637 (2): 1025. doi:10.1086/498560.  edit

See also[edit]