QU Normae

QU Normae, also known as HR 6131, is a blue supergiant star in the constellation Norma. It is also a variable star, thought to be an α Cyg variable.

QU Normae

Location of QU Normae (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Norma
Right ascension	16h 29m 42.32668s[1]
Declination	−46° 14′ 35.6022″[1]
Apparent magnitude (V)	5.37[2] (5.27 - 5.41[3])
Characteristics
Spectral type	B1.5 Iap[4]
U−B color index	−0.44[2]
B−V color index	+0.62[2]
Variable type	α Cyg[3]
Astrometry
Radial velocity (Rv)	−14.80 ± 3.2[5] km/s
Proper motion (μ)	RA: −4.54[1] mas/yr Dec.: −1.51[1] mas/yr
Parallax (π)	1.79 ± 0.70 mas[1]
Distance	approx. 1,800 ly (approx. 600 pc)
Absolute magnitude (MV)	−7.50[6]
Details
Mass	43[7] M☉
Radius	58[8] R☉
Luminosity	417,000[6] L☉
Surface gravity (log g)	2.00[7] cgs
Temperature	17,000[7] K
Rotational velocity (v sin i)	44[7] km/s
Other designations
QU Normae, HD 148379, HIP 80782, HR 6131, CD−45°10697
Database references
SIMBAD	data

The apparent magnitude of QU Normae varies somewhat irregularly between 5.27 and 5.41. The General Catalogue of Variable Stars quotes a period of 4.818 days,^[3] but other research only shows likely periods longer than 10 days.^[9]

A light curve for QU Normae, plotted from Hipparcos data^[10]

QU Normae has a spectral type B1.5 Ia, a luminous supergiant that has swollen and cooled off the main sequence. Surface abundances suggest that it has not yet passed through a red supergiant phase.^[6] Around 1,820 light-years distant, it shines with a luminosity approximately 417,000 times that of the Sun and has a diameter around 58 times that of the Sun.

References

1. Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
2. 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.
3. 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. Bibcode:2009yCat....102025S.
4. Chini, R.; Hoffmeister, V. H.; Nasseri, A.; Stahl, O.; Zinnecker, H. (2012). "A spectroscopic survey on the multiplicity of high-mass stars". Monthly Notices of the Royal Astronomical Society. 424 (3): 1925. arXiv:1205.5238. Bibcode:2012MNRAS.424.1925C. doi:10.1111/j.1365-2966.2012.21317.x. S2CID 119120749.
5. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
6. Lennon, D. J.; Dufton, P. L. (1986). "Evolutionary effects on the surface abundances of an early-type supergiant". Astronomy and Astrophysics. 155: 79. Bibcode:1986A&A...155...79L.
7. 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 (3): 1306. arXiv:1001.3337. Bibcode:2010MNRAS.404.1306F. doi:10.1111/j.1365-2966.2010.16392.x. S2CID 118674151.
8. Wesselink, A. J.; Paranya, K.; Devorkin, K. (1972). "Catalogue of stellar dimensions". Astronomy and Astrophysics Supplement. 7: 257. Bibcode:1972A&AS....7..257W.
9. Van Leeuwen, F.; Van Genderen, A. M.; Zegelaar, I. (1998). "Hipparcos photometry of 24 variable massive stars (α Cygni variables)". Astronomy and Astrophysics Supplement Series. 128: 117–129. Bibcode:1998A&AS..128..117V. doi:10.1051/aas:1998129.
10. "Hipparcos Tools Interactive Data Access". Hipparcos. ESA. Retrieved 8 December 2021.