Verification of Asymptotic Relation for Mixed Modes in Red Giant Stars
arXiv:1406.1825 · doi:10.1093/mnras/stu1697
Abstract
High-precision space observations, such as made by the \kepler\ and \corot\ missions, allow us to detect mixed modes for modes in their high signal-to-noise photometry data. By means of asteroseismology, the inner structure of red giant (RG) stars is revealed the first time with the help of mixed modes. We analyse these mixed modes of a 1.3 M$_{\sun}$ RG model theoretically from the approximate asymptotic descriptions of oscillations. While fitting observed frequencies with the eigenvalue condition for mixed modes, a good estimate of period spacing and coupling strength is also acquired for more evolved models. We show that the behaviour of the mode inertia in a given mode varies dramatically when the coupling is strong. An approximation of period spacings is also obtained from the asymptotic dispersion relation, which provides a good estimate of the coupling strength as well as period spacing when g-mode-like mixed modes are sufficiently dense. By comparing the theoretical coupling strength from the integral expression with the ones from fitting methods, we confirmed that the theoretical asymptotic equation is problematic in the evanescent region due to the potential singularities as well as the use of the Cowling approximation.
arXiv comment10 pages, 11 figures, 4 tables
References in corpus (18)
- Gravity modes as a way to distinguish between hydrogen- and helium-burning red giant stars
- Fast core rotation in red-giant stars revealed by gravity-dominated mixed modes
- Spin down of the core rotation in red giants
- ADIPLS -- the Aarhus adiabatic oscillation package
- ASTEC -- the Aarhus STellar Evolution Code
- Probing the core structure and evolution of red giants using gravity-dominated mixed modes observed with Kepler
- Solar-like oscillations in low-luminosity red giants: first results from Kepler
- Asteroseismology of red giants from the first four months of Kepler data: Global oscillation parameters for 800 stars
- Mixed modes in red-giant stars observed with CoRoT
- Characteristics of solar-like oscillations in red giants observed in the CoRoT exoplanet field
- Oscillations of alpha UMa and other red giants
- Seismic diagnostics for transport of angular momentum in stars 2. Interpreting observed rotational splittings of slowly-rotating red giant stars
- Evolutionary influences on the structure of red-giant acoustic oscillation spectra from 600d of Kepler observations
- Solar-like oscillations in KIC11395018 and KIC11234888 from 8 months of Kepler data
- An Elementary Introduction to the JWKB Approximation
- Masses of subgiant stars from asteroseismology using the coupling strengths of mixed modes
- Modelling a high-mass red giant observed by CoRoT
- Modeling Kepler Observations of Solar-like Oscillations in the Red-giant Star HD 186355
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- Uncertainties on near-core mixing in red-clump stars: effects on the period spacing and on the luminosity of the AGB bump
- On the red-giant luminosity bump
- Analytical modelling of period spacings across the HR diagram
- Testing the asymptotic relation for period spacings from mixed modes of red giants observed with the Kepler mission
- Asteroseismology of 19 low-luminosity red giant stars from Kepler
- Probing the mid-layer structure of red giants I. Mixed-mode coupling factor as a seismic diagnosis
- Gravity mode offset and properties of the evanescent zone in red-giant stars
- Variations of the mixing character of dipolar mixed modes in red giant stars
- A new C-D-like diagram for SPB stars: The variations of period spacing as a signature of evolutionary status
- Evolution of Dipolar Mixed-mode Coupling Factor in Red Giant Stars: Impact of Buoyancy Spike
- Seismic characterization of red giants going through the Helium-core flash
- Asteroseismology of evolved stars with EGGMiMoSA I. Theoretical mixed-mode patterns from the subgiant to the RGB phase
- Solar-like oscillations in Cephei A as seen through SONG and TESS
- Pushing the boundaries of asteroseismic individual frequency modelling: unveiling two evolved very-low metallicity red giants
- Using the phase shift to asymptotically characterize the dipolar mixed modes in post-main-sequence stars
- Realising efficient computation of individual frequencies for red-giant models