Gas Flows Within Cavities of Circumbinary Discs in Eccentric Binary Protostellar Systems. (arXiv:1812.08175v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Mosta_P/0/1/0/all/0/1">Philipp Mösta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Taam_R/0/1/0/all/0/1">Ronald E. Taam</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Duffell_P/0/1/0/all/0/1">Paul C. Duffell</a>
The structure and evolution of gas flows within the cavity of a circumbinary
disc surrounding the stellar components in eccentric binaries are examined via
two dimensional hydrodynamical simulations. The degree to which gas fills the
cavity between the circumstellar discs and the circumbinary disc is found to be
greater for highly eccentric systems, in comparison to low eccentricity
systems, reflecting the spatial extent over which mass enters into the cavity
throughout the orbit. The pattern of the gas flow in the cavity differs for
eccentric binaries from that of binaries in a circular orbit. In particular,
the former reveals tightly wound gas streams and double ring-like structures
for systems characterized by eccentricities, $e geq 0.4$, whereas the latter
only reveal relatively loosely bent streams from the circumbinary disc to the
circumstellar discs. Hence, the existence of the ring-like features can be a
probe of sufficient non circularity of the binary orbital motion. Given that
the inner edge of the circumbinary disc is not very well defined for highly
eccentric systems due to the complex gas structures, it is suggested that the
area of the cavity for high sensitivity imaging observations may prove to be a
more useful diagnostic for probing the effectiveness of circumbinary disc
clearing in the future.
The structure and evolution of gas flows within the cavity of a circumbinary
disc surrounding the stellar components in eccentric binaries are examined via
two dimensional hydrodynamical simulations. The degree to which gas fills the
cavity between the circumstellar discs and the circumbinary disc is found to be
greater for highly eccentric systems, in comparison to low eccentricity
systems, reflecting the spatial extent over which mass enters into the cavity
throughout the orbit. The pattern of the gas flow in the cavity differs for
eccentric binaries from that of binaries in a circular orbit. In particular,
the former reveals tightly wound gas streams and double ring-like structures
for systems characterized by eccentricities, $e geq 0.4$, whereas the latter
only reveal relatively loosely bent streams from the circumbinary disc to the
circumstellar discs. Hence, the existence of the ring-like features can be a
probe of sufficient non circularity of the binary orbital motion. Given that
the inner edge of the circumbinary disc is not very well defined for highly
eccentric systems due to the complex gas structures, it is suggested that the
area of the cavity for high sensitivity imaging observations may prove to be a
more useful diagnostic for probing the effectiveness of circumbinary disc
clearing in the future.
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