التفاصيل البيبلوغرافية
| العنوان: |
Ultraviolet spectrum of FU Ori and a “Compromise” model of the FUor. |
| المؤلفون: |
Kravtsova, A.S., Lamzin, S.A., Errico, L., Vittone, A. |
| المصدر: |
Astronomy Letters; Nov2007, Vol. 33 Issue 11, p755-765, 11p, 1 Diagram, 5 Graphs |
| مصطلحات موضوعية: |
ULTRAVIOLET spectra, STARS, ASTRONOMICAL observations, ABSORPTION, WAVELENGTHS |
| مستخلص: |
We have analyzed the Hubble Space Telescope spectrum of the young star FU Ori in the range 2300–3100 Å. The long-wavelength part of the spectrum is similar to the spectrum of a supergiant with T eff ≃ 5000–6000 K, but the range of wavelengths shorter than ≃2600 Å is dominated by radiation from a region with T eff ≃ 9000 K. We discuss the possibility of explaining these peculiarities of the spectrum, the Al II] 2669.2 emission line profile, and the results of X-ray observations for FU Ori in terms of an accretion disk model whose thickness increases as the star is approached starting from distances ≃1012 cm. Near the star, the disk has the shape of a cone in which only the part of its surface on the far (from the observer) side is visible. The suggested model is a kind of a compromise between the models of a thin α-disk and a supergiant: basically, this is an accretion model, but it resembles a supergiant in observational manifestations. Numerous absorption lines originating in the disk wind are superimposed on the disk spectrum. The wind is a cold ( T ≃ 5000 K), dense ( N e ≃ 1011 cm−3) gas. The number of wind absorption lines in the ultraviolet spectrum of FU Ori increases with decreasing wavelength. This causes a rapid decline in intensity in the short-wavelength part of the spectrum. As a result, the maximum temperature in the disk estimated from low-resolution IUE spectra has been underestimated. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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