QV Normae
| Observation data Epoch J2000.0 ICRS Equinox J2000.0 ICRS | |
|---|---|
| Constellation | Norma |
| Right ascension | 15h 42m 23.36s[1] |
| Declination | −52° 23′ 09.6″ [1] |
| Apparent magnitude (V) | 16.19 - 16.31 [2] |
| Characteristics | |
| Spectral type | B0Iabe[2] |
| Astrometry | |
| Details | |
| Other designations | |
Norma X-2 | |
QV Normae, also known as Norma X-2, is a high mass X-ray binary star system in the constellation Norma. It varies between apparent magnitudes of 16.19 and 16.31.[2]
The X-ray source was first identified in the early 1970s.[3] The nature of the system was discovered in 1978 by astronomers who aligned a visual source of a reddened hot blue-white star with the X-ray source 4U 1538 - 52. The components are a blue-white supergiant estimated to have a mass around 20 times that of the Sun and a neutron star initially estimated at around 1.4 solar masses,[4] later revised to 0.8 solar masses. The stellar wind from the more massive star is drawn to the magnetic poles of neutron star, forming an accretion column and producing X-rays. The system has been estimated to lie anywhere from 4500 to 6500 parsecs (15,000-20,000 light-years) from Earth.[3]
References
- 1 2 "V*QV Normae". SIMBAD Astronomical Database(Centre de donées astronomiques de Strasbourg). Retrieved 20 May 2015.
- 1 2 3 Otero, Sebastian Alberto (23 May 2011). "V QV Nor". The International Variable Star Index. Retrieved 20 May 2015.
- 1 2 Hemphill, Paul B.; Rothschild, Richard E.; Markowitz, Alex; Fürst, Felix; Pottschmidt, Katja; Wilms, Jörn (2014). "A Clumpy Stellar Wind and Luminosity-dependent Cyclotron Line Revealed by the First Suzaku Observation of the High-mass X-Ray Binary 4U 1538-522". The Astrophysical Journal. 792 (1): 15. arXiv:1407.1028
. Bibcode:2014ApJ...792...14H. doi:10.1088/0004-637X/792/1/14. - ↑ Reynolds, A. P.; Bell, S. A.; Hilditch, R. W. (1992). "Optical spectroscopy of the massive X-ray binary QV Nor (4U 1538 - 52)". Monthly Notices of the Royal Astronomical Society. 256 (4): 631–40. Bibcode:1992MNRAS.256..631R. doi:10.1093/mnras/256.4.631. ISSN 0035-8711.