Inversion of rotation profile for solar-like stars

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Inversion of rotation profile for solar-like stars

• Jérémie Lochard

IAS 19/11/04
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Rotational splitting rotation lifts the
degeneracy
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Rotational splitting
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Rotational splitting
what we observe
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Rotational splitting
what we observe
what we search
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Rotational splitting
what we observe
what we compute from models
what we search
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Helioseismology
Structure and rotation inversion gave strong
constraints on solar models
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Helioseismology
Structure and rotation inversion gave strong
constraints on solar models
Asteroseismology
Restricted mode set l0,1,2(,3) (up to a few
1000 for the Sun)
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Helioseismology
Structure and rotation inversion gave strong
constraints on solar models
Asteroseismology
Restricted mode set l0,1,2(,3) (up to a few
1000 for the Sun)
Our aim is rotational inversion possible
for some specific solar-like stars ? give
selection constraints
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Helioseismology
Structure and rotation inversion gave strong
constraints on solar models
Asteroseismology
Restricted mode set l0,1,2(,3) (up to a few
1000 for the Sun)
Our aim is rotational inversion possible
for some specific solar-like stars ? give
selection constraints
Other stars may show modes with different nature
from those observed on the Sun
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With evolution g-mode cavity appears at the
edge of the convective core
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With evolution g-mode cavity appears at the
edge of the convective core look for evolved
stars (but still on the main sequence)
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Eigen-functions and rotational kernels
P modes
Mixed modes
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Mode set selection
Amplitude computation from the excitation and
damping rates
Selection threshold from the COROT specifications
mixed modes
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Mode set selection
Amplitude computation from the excitation and
damping rates
Selection threshold from the COROT specifications
Mode amplitudes increase with mass look for
massive stars with outer convective zone
mixed modes
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Building a trial model to compute the rotational
kernels
HR diagram constraints Effective temperature
and luminosity
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Building a trial model to compute the rotational
kernels
HR diagram constraints Effective temperature
and luminosity
Seismic constraints
large separationglobal constraint (mean density)
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Building a trial model to compute the rotational
kernels
HR diagram constraints Effective temperature
and luminosity
Seismic constraints
large separationglobal constraint mean density
small separation constraint on the deep interior
(evolution stage )
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Inversion
inversion
Kernels from the initial model
forward
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Inversion
Kernels from the initial model
Kernels from the trial model
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Inversion
Kernels from the initial model
Kernels from the trial model
Kernels from the trial model and random errors
added
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Forward check
computing the splittings from the recovered
rotation profile
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Constraints on the rotational inversion for
solar-like stars Mass (modes
amplitude) Evolution (mixed
modes) Surface velocity (relative
precision)
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Constraints on the rotational inversion for
solar-like stars Mass (modes
amplitude) Evolution (mixed
modes) Surface velocity (relative
precision)
Needs stellar parameters (Teff, luminosity,
surface chemical composition)
long observation periods and low noise level
(Corot, Eddington)