Astronomy:Vela X-1
| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| Constellation | Vela |
| Right ascension | 09h 02m 06.861s[2] |
| Declination | −40° 33′ 16.90″[2] |
| Apparent magnitude (V) | 6.87 |
| Characteristics | |
| Spectral type | B0.5Ia |
| Apparent magnitude (B) | 7.301 |
| Apparent magnitude (V) | 6.926 |
| Apparent magnitude (J) | 5.833±0.020 |
| Apparent magnitude (H) | 5.705±0.034 |
| Apparent magnitude (K) | 5.596±0.024 |
| U−B color index | −0.51[3] |
| B−V color index | 0.50[3] |
| Variable type | Complex[citation needed] |
| Astrometry | |
| Proper motion (μ) | RA: −4.822[2] mas/yr Dec.: 9.282[2] mas/yr |
| Parallax (π) | 0.4962 ± 0.0152[2] mas |
| Distance | 6,600 ± 200 ly (2,020 ± 60 pc) |
| Other designations | |
Supergiant component: GP Vel, HD 77581, SAO 220767, HIP 44368, CPD−40°3072, CD−40°4838; X-ray component: 1XRS 09002-403, 1RXS J090207.0-403311, 4U 0900-40 | |
| Database references | |
| SIMBAD | data |
Vela X-1 is a pulsing, eclipsing high-mass X-ray binary (HMXB) system, associated with the Uhuru source 4U 0900-40 and the supergiant star HD 77581. The X-ray emission of the neutron star is caused by the capture and accretion of matter from the stellar wind of the supergiant companion. Vela X-1 is the prototypical detached HMXB.[4]
The orbital period of the system is 8.964 days, with the neutron star being eclipsed for about two days of each orbit by HD 77581. It has been given the variable star designation GP Velorum, and it varies from visual magnitude 6.76 to 6.99.[5] The spin period of the neutron star is about 283 seconds, and gives rise to strong X-ray pulsations. The mass of the pulsar is estimated to be at least 1.88±0.13 solar masses.[6]
Characteristics
Long term monitoring of the spin period shows small random increases and decreases over time similar to a random walk.[7] The accreting matter causes the random spin period changes. However, a recent study has detected nearly periodic spin period reversals in Vela X-1 on long time-scales of about 5.9 years.[8]
See also
- High-mass X-ray binary
- List of X-ray pulsars
- X-ray binary
References
- ↑ Tjemkes, S. A.; Zuiderwijk, E. J.; van Paradijs, J. (January 1986). "Optical light curves of massive X-ray binaries". Astronomy and Astrophysics 154: 77–91. Bibcode: 1986A&A...154...77T. https://ui.adsabs.harvard.edu/abs/1986A&A...154...77T. Retrieved 29 April 2022.
- ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 Klare, G.; Neckel, T. (1977). "UBV, Hβ and polarization measurements of 1660 southern OB stars". Astronomy and Astrophysics Supplement 27: 215. Bibcode: 1977A&AS...27..215K.
- ↑ Mauche, C. W.; Liedahl, D. A.; Akiyama, S.; Plewa, T. (2007). "Hydrodynamic and Spectral Simulations of HMXB Winds". Progress of Theoretical Physics Supplement 169: 196–199. doi:10.1143/PTPS.169.196. Bibcode: 2007PThPS.169..196M.
- ↑ "GP Vel". AAVSO. https://www.aavso.org/vsx/index.php?view=detail.top&oid=37614.
- ↑ Quaintrell, H. (2003). "The mass of the neutron star in Vela X-1 and tidally induced non-radial oscillations in GP Vel". Astronomy and Astrophysics 401: 313–324. doi:10.1051/0004-6361:20030120. Bibcode: 2003A&A...401..313Q.
- ↑ Bildsten, L. (1997). "Observations of Accreting Pulsars". The Astrophysical Journal Supplement Series 113 (2): 367–408. doi:10.1086/313060. Bibcode: 1997ApJS..113..367B.
- ↑ Chandra, A. D. (2021). "Detection of nearly periodic spin period reversals in Vela X-1 on long time-scales: inkling of solar-like cycle in the donor star?". Monthly Notices of the Royal Astronomical Society 508 (3): 4429–4442. doi:10.1093/mnras/stab2382. Bibcode: 2021MNRAS.508.4429C.
External links
- Spin frequency history of Vela X-1
- Long-term spin period evolution of Vela X-1 for about five decades
Coordinates: 
09h 02m 06.860s, −40° 33′ 16.91″
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