Mu Normae

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μ Normae
Norma constellation map.svg
Red circle.svg

Location of μ Nor (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Norma
Right ascension 16h 34m 05.02028s[1]
Declination −44° 02′ 43.1281″[1]
Apparent magnitude (V) 4.91[2]
Spectral type O9.7Iab[3]
Apparent magnitude (U) 4.05[4]
Apparent magnitude (B) 4.99[4]
Apparent magnitude (J) 4.74[4]
Apparent magnitude (H) 4.679[5]
Apparent magnitude (K) 4.612[5]
U−B color index −0.84[4]
B−V color index +0.05[4]
Variable type Suspected α Cygni[6]
Radial velocity (Rv) +6.30[7] km/s
Proper motion (μ) RA: 0.02[1] mas/yr
Dec.: −1.98[1] mas/yr
Parallax (π) 0.78 ± 0.33[1] mas
Distance 1,000[8] pc
Absolute magnitude (MV) -6.45[2]
Mass 40 M
Radius 25[2] R
Luminosity (bolometric) 339,000[2] L
Surface gravity (log g) 3.10 cgs
Temperature 28,500 K
Rotational velocity (v sin i) 61 km/s
Age 4.7[10] Myr
Other designations
Mu Normae, HD 149038, HR 6155, HIP 81122, CD−43°10900
Database references

Mu Normae is a blue supergiant star of spectral type O9.7 Iab in the constellation Norma.

It is 330,000 times the luminosity of the sun and 40 times its mass. It is suspected of being an Alpha Cygni variable, which are named after the similar star Deneb. Being a blue supergiant, it is likely to become a red supergiant in a few million years and eventually a type-II supernova.[citation needed]

It is in the same direction and at the same distance as the faint open cluster NGC 6169, although it is brighter than the combined magnitude of all the other stars in the cluster. It was considered the prototype of the μ Normae class of open clusters by Collinder.[11]


  1. ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Lefever, K.; Puls, J.; Aerts, C. (2007). "Statistical properties of a sample of periodically variable B-type supergiants". Astronomy and Astrophysics. 463 (3): 1093–1109. arXiv:astro-ph/0611484Freely accessible. Bibcode:2007A&A...463.1093L. doi:10.1051/0004-6361:20066038. 
  3. ^ Sota, A.; Maíz Apellániz, J.; Morrell, N.I.; Barbá, R.H.; Walborn, N.R.; Gamen, R.C.; Arias, J.I.; Alfaro, E.J. (2014). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement. 211 (1): 84. arXiv:1312.6222Freely accessible. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. 10. 
  4. ^ a b c d e Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D. 
  5. ^ a b Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; Carpenter, J. M.; Chester, T.; Cambresy, L.; Evans, T.; Fowler, J.; Gizis, J.; Howard, E.; Huchra, J.; Jarrett, T.; Kopan, E. L.; Kirkpatrick, J. D.; Light, R. M.; Marsh, K. A.; McCallon, H.; Schneider, S.; Stiening, R.; Sykes, M.; Weinberg, M.; Wheaton, W. A.; Wheelock, S.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". VizieR On-line Data Catalog: II/246. Originally published in: 2003yCat.2246....0C. 2246. Bibcode:2003yCat.2246....0C. 
  6. ^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1: 02025. Bibcode:2009yCat....102025S. 
  7. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. 
  8. ^ 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): 1025–1039. arXiv:astro-ph/0510252Freely accessible. Bibcode:2006ApJ...637.1025F. doi:10.1086/498560. 
  9. ^ Fraser, M.; Dufton, P. L.; Hunter, I.; Ryans, R. S. I. (2010). "Atmospheric parameters and rotational velocities for a sample of Galactic B-type supergiants". Monthly Notices of the Royal Astronomical Society. 404: 1306. arXiv:1001.3337Freely accessible. Bibcode:2010MNRAS.404.1306F. doi:10.1111/j.1365-2966.2010.16392.x. 
  10. ^ Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410: 190–200. arXiv:1007.4883Freely accessible. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. 
  11. ^ Collinder, Per (1931). "On Structural Properties of Open Galactic Clusters and their Spatial Distribution. Catalog of Open Galactic Clusters". Annals of the Observatory of Lund. 2: B1–B46. Bibcode:1931AnLun...2....1C. 

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