TY - JOUR
T1 - Physics of tidal dissipation in early-type stars and white dwarfs
T2 - Hydrodynamical simulations of internal gravity wave breaking in stellar envelopes
AU - Su, Yubo
AU - Lecoanet, Daniel
AU - Lai, Dong
N1 - Funding Information:
This work has been supported in part by the National Science Foundation grant AST-17152. YS is supported by the National Aeronautics and SpaceAdministration (NASA) FINESST grant 19- ASTRO19-0041. DL is supported by the Princeton Center for Theoretical Sciences and Lyman Spitzer Jr fellowships. Computations were conducted with support by the NASA High End Computing Program through the NASA Advanced Supercomputing Division at Ames Research Center on Pleiades with allocation GID s1647.
Funding Information:
This work has been supported in part by the National Science Foundation grant AST-17152. YS is supported by the National Aeronautics and Space Administration (NASA) FINESST grant 19-ASTRO19-0041. DL is supported by the Princeton Center for The- oretical Sciences and Lyman Spitzer Jr fellowships. Computations were conducted with support by the NASA High End Computing Program through the NASA Advanced Supercomputing Division at Ames Research Center on Pleiades with allocation GID s1647.
Publisher Copyright:
© 2020 The Author(s).
PY - 2020
Y1 - 2020
N2 - In binaries composed of either early-type stars or white dwarfs, the dominant tidal process involves the excitation of internal gravity waves (IGWs), which propagate towards the stellar surface, and their dissipation via non-linear wave breaking. We perform 2D hydrodynamical simulations of this wave breaking process in a stratified, isothermal atmosphere. We find that, after an initial transient phase, the dissipation of the IGWs naturally generates a sharp critical layer, separating the lower stationary region (with no mean flow) and the upper 'synchronized' region (with the mean flow velocity equal to the horizontal wave phase speed). While the critical layer is steepened by absorption of these waves, it is simultaneously broadened by Kelvin-Helmholtz instabilities such that, in steady state, the critical layer width is determined by the Richardson criterion. We study the absorption and reflection of incident waves off the critical layer and provide analytical formulae describing its long-term evolution. The result of this study is important for characterizing the evolution of tidally heated white dwarfs and other binary stars.
AB - In binaries composed of either early-type stars or white dwarfs, the dominant tidal process involves the excitation of internal gravity waves (IGWs), which propagate towards the stellar surface, and their dissipation via non-linear wave breaking. We perform 2D hydrodynamical simulations of this wave breaking process in a stratified, isothermal atmosphere. We find that, after an initial transient phase, the dissipation of the IGWs naturally generates a sharp critical layer, separating the lower stationary region (with no mean flow) and the upper 'synchronized' region (with the mean flow velocity equal to the horizontal wave phase speed). While the critical layer is steepened by absorption of these waves, it is simultaneously broadened by Kelvin-Helmholtz instabilities such that, in steady state, the critical layer width is determined by the Richardson criterion. We study the absorption and reflection of incident waves off the critical layer and provide analytical formulae describing its long-term evolution. The result of this study is important for characterizing the evolution of tidally heated white dwarfs and other binary stars.
KW - Binaries:close
KW - Hydrodynamics
KW - Waves
KW - White dwarfs
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U2 - 10.1093/MNRAS/STAA1306
DO - 10.1093/MNRAS/STAA1306
M3 - Article
AN - SCOPUS:85096771048
VL - 495
SP - 1239
EP - 1251
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -