| Autor: |
Sander, Andreas Alexander Christoph (Dr. rer. nat.), Fürst, F., Kretschmar, P., Oskinova, Lida M. (apl. Prof.), Todt, Helge (Dr. rer. n.), Hainich, Rainer (Dr. rer. n.), Shenar, Tomer (Dr.), Hamann, Wolf-Rainer (Prof. Dr.) |
| Jazyk: |
angličtina |
| Rok vydání: |
2018 |
| Předmět: |
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| Popis: |
Aims. To gain a realistic picture of the donor star in Vela X-1, we constructed a hydrodynamically consistent atmosphere model describing the wind stratification while properly reproducing the observed donor spectrum. To investigate how X-ray illumination affects the stellar wind, we calculated additional models for different X-ray luminosity regimes. Methods. We used the recently updated version of the Potsdam Wolf-Rayet code to consistently solve the hydrodynamic equation together with the statistical equations and the radiative transfer. Results. The wind flow in Vela X-1 is driven by ions from various elements, with Fe III and S III leading in the outer wind. The model-predicted mass-loss rate is in line with earlier empirical studies. The mass-loss rate is almost unaffected by the presence of the accreting NS in the wind. The terminal wind velocity is confirmed at u(infinity) approximate to 600 km s(-1). On the other hand, the wind velocity in the inner region where the NS is located is only approximate to 100 km s(-1), which is not expected on the basis of a standard beta-velocity law. In models with an enhanced level of X-rays, the velocity field in the outer wind can be altered. If the X-ray flux is too high, the acceleration breaks down because the ionization increases. Conclusions. Accounting for radiation hydrodynamics, our Vela X-1 donor atmosphere model reveals a low wind speed at the NS location, and it provides quantitative information on wind driving in this important HMXB. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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