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The oscillation frequencies observed in Sun-like stars are susceptible to being shifted by magnetic activity effects. The measured shifts depend on a complex relationship involving the mode type, the field strength and spatial distribution…

Solar and Stellar Astrophysics · Physics 2021-02-17 Alexandra E. L. Thomas , William J. Chaplin , Sarbani Basu , Ben Rendle , Guy Davies , Andrea Miglio

In the Sun, the properties of acoustic modes are sensitive to changes in the magnetic activity. In particular, mode frequencies are observed to increase with increasing activity level. Thanks to CoRoT and Kepler, such variations have been…

Frequency separations used to infer global properties of stars through asteroseismology can change depending on the strength and at what epoch of the stellar cycle the p-mode frequencies are measured. In the Sun these variations have been…

Solar and Stellar Astrophysics · Physics 2015-05-20 O. L. Creevey , D. Salabert , R. A. Garcia

In the Sun, the frequencies of the acoustic modes are observed to vary in phase with the magnetic activity level. These frequency variations are expected to be common in solar-type stars and contain information about the activity-related…

Solar and Stellar Astrophysics · Physics 2018-08-01 A. R. G. Santos , T. L. Campante , W. J. Chaplin , M. S. Cunha , M. N. Lund , R. Kiefer , D. Salabert , R. A. Garcia , G. R. Davies , Y Elsworth , R. Howe

During the last decade, our understanding of stellar physics and evolution has undergone a tremendous revolution thanks to asteroseismology. Space missions such as CoRoT, \kep, K2, and TESS have already been observing millions of stars…

Solar and Stellar Astrophysics · Physics 2024-12-25 Savita Mathur

The principal aim of observational helioseismology is to determine mode parameters of the solar oscillations as accurately as possible. Yet estimates of the mode parameters are subject to many sources of noise, including inevitable gaps in…

Astrophysics · Physics 2009-11-07 Heon-Young Chang

Magnetic activity is a ubiquitous feature of stars with convective outer layers, with implications from stellar evolution to planetary atmospheres. Investigating the mechanisms responsible for the observed stellar activity signals from days…

Solar and Stellar Astrophysics · Physics 2023-10-17 Emre Işık , Jennifer L. van Saders , Ansgar Reiners , Travis S. Metcalfe

Small cyclic variations in the frequencies of acoustic modes are expected to be a common phenomenon in solar-like pulsators, as a result of stellar magnetic activity cycles. The frequency variations observed throughout the solar and stellar…

Solar and Stellar Astrophysics · Physics 2015-06-12 A. R. G. Santos , M. S. Cunha , J. J. G. Lima

Context. The Sun and solar-like stars undergo activity cycles for which the underlying mechanisms are not well understood. The oscillations of the Sun are known to vary with its activity cycle and these changes provide diagnostics on the…

Solar and Stellar Astrophysics · Physics 2017-02-08 René Kiefer , Ariane Schad , Guy Davies , Markus Roth

Solar oscillation frequencies change with the level of magnetic activity. Localizing subsurface magnetic field concentrations in the Sun with helioseismology will help us to understand the solar dynamo. Because the magnetic fields are not…

Solar and Stellar Astrophysics · Physics 2018-02-28 René Kiefer , Markus Roth

Magnetic activity effects are typically neglected in asteroseismic modelling of solar-type stars, presuming that these effects can be accounted for in the parametrisation of the surface effects. It was however demonstrated that magnetic…

Solar and Stellar Astrophysics · Physics 2025-07-16 Jérôme Bétrisey , Anne-Marie Broomhall , Sylvain N. Breton , Rafael A. García , Henry Davenport , Oleg Kochukhov

Magnetic fields and stellar spots can alter the equivalent widths of absorption lines in stellar spectra, varying during the activity cycle. This also influences the information that we derive through spectroscopic analysis. In this study…

Oscillation mode frequencies of stars are typically treated as static for a given stellar model. However, in reality they can be perturbed by time varying sources such as magnetic fields and flows. We calculate the sensitivities of radial…

Solar and Stellar Astrophysics · Physics 2020-07-01 René Kiefer , Anne-Marie Broomhall

Stars are changing entities in a constant evolution during their lives. At non-secular time scales (from seconds to years) the effect of dynamical processes such as convection, rotation, and magnetic fields can modify the stellar…

Solar and Stellar Astrophysics · Physics 2019-07-09 S. Mathur , J. Ballot , R. A. Garcia

The variations of the frequencies of the low-degree acoustic oscillations in the Sun induced by magnetic activity show a dependence with radial order. The frequency shifts are observed to increase towards higher-order modes to reach a…

Solar and Stellar Astrophysics · Physics 2018-04-04 D. Salabert , C. Régulo , F. Pérez Hernández , R. A. García

The success of helioseismology is due to its capability to accurately measure the p-mode parameters of the solar eigenmode spectrum, which allow us to infer unique information about the internal structure and dynamics of the Sun. It also…

Solar and Stellar Astrophysics · Physics 2011-10-14 D. Salabert

Stellar oscillations are key to unravelling stars' properties, such as their mass, radius and age. Amplitudes of acoustic modes in solar-like stars are intrinsically linked to their convective turbulent excitation source, which in turn is…

Solar and Stellar Astrophysics · Physics 2024-07-11 Leïla Bessila , Stéphane Mathis

The rotational evolution of cool stars is governed by magnetised stellar winds which slow the stellar rotation during their main sequence lifetimes. Magnetic variability is commonly observed in Sun-like stars, and the changing strength and…

Solar and Stellar Astrophysics · Physics 2018-09-19 Adam J. Finley , Sean P. Matt , Victor See

In solar-like stars, acoustic modes provide the main way of probing their internal structure and dynamics. Although these modes are expected to be ubiquitous in stars with convective envelopes, Kepler observations reveal that a significant…

Solar and Stellar Astrophysics · Physics 2026-04-30 Arthur Le Saux , Leïla Bessila , Stéphane Mathis

Asteroseismology provides powerful means to probe stellar interiors. The oscillations frequencies are closely related to stellar interior properties via the density and sound speed profiles. Since these are tightly linked with the mass and…

Astrophysics · Physics 2015-05-13 Yveline Lebreton , Josefina Montalban
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