Evolution and pulsations of population I post-AGB stars. (arXiv:1907.01230v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Fadeyev_Y/0/1/0/all/0/1">Yu.A. Fadeyev</a>
Evolutionary calculations of population I stars with initial masses
$M_0=1M_odot$, $1.5M_odot$ and $2M_odot$ were carried out up to the stage of
the proto–planetary nebula. Selected models of post–AGB evolutionary
sequences with effective temperatures $3.6times 10^3,mathrm{K}lesssim
T_mathrm{eff}lesssim 2times 10^4,mathrm{K}$ were used as initial
conditions in calculations of self–escited stellar oscillations. For the first
time the sequences of hydrodynamic models of radially pulsating post–AGB stars
were computed using the self–consistent solution of the equations of radiation
hydrodynamics and time–dependent convection. Within this range of effective
temperatures the post–AGB stars are the fundamental mode pulsators with period
decreasing as the star evolves from $Piapprox 300$ day to several days.
Period fluctuations are due to nonlinear effects and are most prominent at
effective temperatures $T_mathrm{eff} < 5000$K. The amplitude of bolometric
light variations is $Delta M_mathrm{bol}approx 1$ at $T_mathrm{eff}
lesssim 6000$K and rapidly decreases with increasing $T_mathrm{eff}$. The
theoretical dependence of the pulsation period as a function of effective
temperature obtained in the study can be used as a criterion for the
evolutionary status of pulsating variables suspected to be post--AGB stars.
Evolutionary calculations of population I stars with initial masses
$M_0=1M_odot$, $1.5M_odot$ and $2M_odot$ were carried out up to the stage of
the proto–planetary nebula. Selected models of post–AGB evolutionary
sequences with effective temperatures $3.6times 10^3,mathrm{K}lesssim
T_mathrm{eff}lesssim 2times 10^4,mathrm{K}$ were used as initial
conditions in calculations of self–escited stellar oscillations. For the first
time the sequences of hydrodynamic models of radially pulsating post–AGB stars
were computed using the self–consistent solution of the equations of radiation
hydrodynamics and time–dependent convection. Within this range of effective
temperatures the post–AGB stars are the fundamental mode pulsators with period
decreasing as the star evolves from $Piapprox 300$ day to several days.
Period fluctuations are due to nonlinear effects and are most prominent at
effective temperatures $T_mathrm{eff} < 5000$K. The amplitude of bolometric
light variations is $Delta M_mathrm{bol}approx 1$ at $T_mathrm{eff}
lesssim 6000$K and rapidly decreases with increasing $T_mathrm{eff}$. The
theoretical dependence of the pulsation period as a function of effective
temperature obtained in the study can be used as a criterion for the
evolutionary status of pulsating variables suspected to be post–AGB stars.
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