Sensitivity analysis of the solar rotation to helioseismic data from GONG, GOLF and MDI observations

Abstract

Accurate determination of the rotation rate in the radiative zone of the sun from helioseismic observations requires rotational frequency splittings of exceptional quality as well as reliable inversion techniques. We present here inferences based on mode parameters calculated from 2088-days long MDI, GONG and GOLF time series that were fitted to estimate very low frequency rotational splittings (nu < 1.7 mHz). These low frequency modes provide data of exceptional quality, since the width of the mode peaks is much smaller than the rotational splitting and hence it is much easier to separate the rotational splittings from the effects caused by the finite lifetime and the stochastic excitation of the modes. We also have implemented a new inversion methodology that allows us to infer the rotation rate of the radiative interior from mode sets that span l=1 to 25. Our results are compatible with the sun rotating like a rigid solid in most of the radiative zone and slowing down in the core (R_sun < 0.2). A resolution analysis of the inversion was carried out for the solar rotation inverse problem. This analysis effectively establishes a direct relationship between the mode set included in the inversion and the sensitivity and information content of the resulting inferences. We show that such an approach allows us to determine the effect of adding low frequency and low degree p-modes, high frequency and low degree p-modes, as well as some g-modes on the derived rotation rate in the solar radiative zone, and in particular the solar core. We conclude that the level of uncertainties that is needed to infer the dynamical conditions in the core when only p-modes are included is unlikely to be reached in the near future, and hence sustained efforts are needed towards the detection and characterization of g-modes.

arXiv commentAccepted for publication in Astrophysical journal. 15 pages, 19 figures

References in corpus (1)

• The Rotation Of The Deep Solar Layers

Cited by in corpus (16)

• Seismic diagnostics for transport of angular momentum in stars 1. Rotational splittings from the PMS to the RGB
• Asteroseismology of solar-type stars
• On the Stability of Non Force-Free Magnetic Equilibria in Stars
• Seismic and dynamical solar models i-the impact of the solar rotation history on neutrinos and seismic indicators
• Solar neutrinos, helioseismology and the solar internal dynamics
• Alive and well: a short review about standard solar models
• Lithium depletion and angular momentum transport in solar-type stars
• Influence of Low-Degree High-Order p-Mode Splittings on the Solar Rotation Profile
• The Dynamics of the Solar Radiative Zone
• Lithium depletion and angular momentum transport in F-type and G-type stars in Galactic open clusters
• New insights on the solar core
• Observational techniques to measure solar and stellar oscillations
• Using Lithium and Beryllium to Study Structure and Evolution of Rotating Stars
• Concluding remarks on Solar and Stellar Activities and related planets
• Co-existence of Internal Gravity Waves and Tayler-Spruit Magnetic Fields in the Radiative Core of Low-mass Stars
• The dynamics of the radiative zone of the Sun