Origin of the focusing of the stellar wind from the red giant in the orbital region of the symbiotic binary EG Andromedae
Authors:
Natalia Shagatova, Augustin Skopal, Emil Kundra, Richard Komzik, Sergey Shugarov, Theodor Pribulla, Viktoriia Krushevska
Image & caption:
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Image caption::
Left: The values of the rotational velocity at the distance r from the center of the red giant in units of its radius Rg obtained by modeling broadened profiles of 10 absorption lines of neutral iron at different orbital phases φ. Right: Sketch of the orbital plane showing increased densities of the stellar wind in the vicinity of the red giant approximately towards the white dwarf.
Description:
EG Andromedae belongs to the quiescent symbiotic binaries, in which part of the mass escaping from the red giant through the stellar wind is transferred to its companion - a white dwarf. In the past, we managed to find out by two independent methods that the wind from the giant is not evenly distributed in its surroundings, but is enhanced near the orbital plane. However, the reason for this asymmetry was not understood. Modeling the broadened profiles of absorption lines of iron atoms at different orbital phases, we revealed possible causes of the focusing of the stellar wind towards the orbital plane. We determined the rotational velocity of the red giant of 11 km/s, which is sufficient for the stellar wind to be compressed due to the rotational motion. In addition, we found that the highest densities of the stellar wind are in the vicinity of the red giant towards the white dwarf. This means that the stellar wind is probably focused towards the orbital plane also due to the gravitational effect of the white dwarf. Our result independently confirms the enhanced mass transfer via the wind to the white dwarf in symbiotic binaries.
Reference:
Astronomy & Astrophysics, Volume 676, id.A98, 12 pp. (2023)
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