Abstract
The evolutionary excitation dynamics of the gravitational instability in a self-gravitating viscoelastic non-thermal polytropic complex fluid is semi-analytically explored on the astro-scales of space and time. The polytropic equation of state is well validated for the hydrostatic equilibrium established by a perfect heating-cooling balancing in the uni-component complex fluid. We apply a generalized gravitating hydrodynamic model in the concurrent presence of buoyancy, thermal fluctuations, volumetric expansion, and so forth. A normal mode (local) analysis yields a quadratic linear dispersion relation with a unique set of multi-parametric coefficients. The analytical reliability is checked by comparing with the existing reports on purely ideal inviscid nebular fluids and non-ideal viscoelastic fluids in isolation. It is seen that, unlike the normal instability mechanisms, the instability here remains unaffected due to the thermo-mechanical diffusion processes. The stabilizing (destabilizing) and accelerating (decelerating) factors of the instability are illustratively explored. The instability features are judged in the light of both impure non-ideal viscoelastic fluid and pure ideal inviscid nebular fluid scenarios. The relevancy of our exploration in superdense compact viscoelastic astro-objects and their surrounding atmospheres is summarily outlined.
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Acknowledgements
Active cooperation with Tezpur University is thankfully acknowledged. The valuable comments and insightful suggestions by the anonymous learned referees are duly mentioned. Lastly, financial support by SERB (Grant- EMR / 2017 / 003222) is thankfully recognized.
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Karmakar, P.K., Kalita, D. Dynamics of gravitational instability excitation in viscoelastic polytropic fluids. Astrophys Space Sci 363, 239 (2018). https://doi.org/10.1007/s10509-018-3460-5
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DOI: https://doi.org/10.1007/s10509-018-3460-5