Growth and dissipation of Be star discs in misaligned binary systems

Autor(es)

Suffak, M. ^[1] ; Jones, C. E. ^[1] ; Carciofi, A. C. ^[2]

Afiliação do(s) autor(es)

^[1] Western Univ, Dept Phys & Astron, London, ON N6A 3K7 - Canada

^[2] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 509, n. 1, p. 931-944, JAN 2022.
• Citações Web of Science: 2

Resumo

We use a three-dimensional smoothed particle hydrodynamics code to simulate growth and dissipation of Be star discs in systems where the binary orbit is misaligned with respect to the spin axis of the primary star. We investigate six different scenarios of varying orbital period and misalignment angle, feeding the disc at a constant rate for 100 orbital periods, and then letting the disc dissipate for 100 orbital periods. During the disc growth phase, we find that the binary companion tilts the disc away from its initial plane at the equator of the primary star before settling to a constant orientation after 40-50 orbital periods. While the mass-injection into the disc is ongoing, the tilting of the disc can cause material to reaccrete on to the primary star prematurely. Once disc dissipation begins, usually the disc precesses about the binary companion's orbital axis with precession periods ranging from 20 to 50 orbital periods. In special cases, we detect phenomena of disc tearing, as well as Kozai-Lidov oscillations of the disc. These oscillations reach a maximum eccentricity of about 0.6, and a minimum inclination of about 20 degrees with respect to the binary's orbit. We also find the disc material to have highly eccentric orbits beyond the transition radius, where the disc changes from being dominated by viscous forces, to heavily controlled by the companion star, in contrast to its nearly circular motion inwards of the transition radius. Finally, we offer predictions to how these changes will affect Be star observables. (AU)

• Processo FAPESP: 19/13354-1 - Discos de decréscimo e outflows em torno de estrelas em rápida rotação
• Beneficiário: Alex Cavaliéri Carciofi
• Modalidade de apoio: Auxílio à Pesquisa - Regular