Asteroseismic masses, ages, and core properties of $gamma$ Doradus stars using gravito-inertial dipole modes and spectroscopy. (arXiv:1902.06746v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Mombarg_J/0/1/0/all/0/1">Joey S. G. Mombarg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Reeth_T/0/1/0/all/0/1">Timothy Van Reeth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pedersen_M/0/1/0/all/0/1">May G. Pedersen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Molenberghs_G/0/1/0/all/0/1">Geert Molenberghs</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bowman_D/0/1/0/all/0/1">Dominic M. Bowman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnston_C/0/1/0/all/0/1">Cole Johnston</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aerts_C/0/1/0/all/0/1">Conny Aerts</a>
The asteroseismic modelling of period spacing patterns from gravito-inertial
modes in stars with a convective core is a high-dimensional problem. We utilise
the measured period spacing pattern of prograde dipole gravity modes (acquiring
$Pi_0$), in combination with the effective temperature ($T_{rm eff}$) and
surface gravity ($log g$) derived from spectroscopy, to estimate the
fundamental stellar parameters and core properties of 37 $gamma~$Doradus
($gamma~$Dor) stars whose rotation frequency has been derived from
$textit{Kepler}$ photometry. We make use of two 6D grids of stellar models,
one with step core overshooting and one with exponential core overshooting, to
evaluate correlations between the three observables $Pi_0$, $T_{rm eff}$, and
$log g$ and the mass, age, core overshooting, metallicity, initial hydrogen
mass fraction and envelope mixing. We provide multivariate linear model recipes
relating the stellar parameters to be estimated to the three observables
($Pi_0$, $T_{rm eff}$, $log g$). We estimate the (core) mass, age, core
overshooting and metallicity of $gamma~$Dor stars from an ensemble analysis
and achieve relative uncertainties of $sim!10$ per cent for the parameters.
The asteroseismic age determination allows us to conclude that efficient
angular momentum transport occurs already early on during the main sequence. We
find that the nine stars with observed Rossby modes occur across almost the
entire main-sequence phase, except close to core-hydrogen exhaustion. Future
improvements of our work will come from the inclusion of more types of detected
modes per star, larger samples, and modelling of individual mode frequencies.
The asteroseismic modelling of period spacing patterns from gravito-inertial
modes in stars with a convective core is a high-dimensional problem. We utilise
the measured period spacing pattern of prograde dipole gravity modes (acquiring
$Pi_0$), in combination with the effective temperature ($T_{rm eff}$) and
surface gravity ($log g$) derived from spectroscopy, to estimate the
fundamental stellar parameters and core properties of 37 $gamma~$Doradus
($gamma~$Dor) stars whose rotation frequency has been derived from
$textit{Kepler}$ photometry. We make use of two 6D grids of stellar models,
one with step core overshooting and one with exponential core overshooting, to
evaluate correlations between the three observables $Pi_0$, $T_{rm eff}$, and
$log g$ and the mass, age, core overshooting, metallicity, initial hydrogen
mass fraction and envelope mixing. We provide multivariate linear model recipes
relating the stellar parameters to be estimated to the three observables
($Pi_0$, $T_{rm eff}$, $log g$). We estimate the (core) mass, age, core
overshooting and metallicity of $gamma~$Dor stars from an ensemble analysis
and achieve relative uncertainties of $sim!10$ per cent for the parameters.
The asteroseismic age determination allows us to conclude that efficient
angular momentum transport occurs already early on during the main sequence. We
find that the nine stars with observed Rossby modes occur across almost the
entire main-sequence phase, except close to core-hydrogen exhaustion. Future
improvements of our work will come from the inclusion of more types of detected
modes per star, larger samples, and modelling of individual mode frequencies.
http://arxiv.org/icons/sfx.gif
