Related papers: Mixed Modes and Asteroseismic Surface Effects: II.…
Stellar oscillations can be of topological origin. We reveal this deep and so-far hidden property of stars by establishing a novel parallel between stars and topological insulators. We construct an hermitian problem to derive the expression…
Asteroseismic studies of red giants generally assume that the oscillation modes can be treated as linear perturbations to the background star. However, observations by the Kepler mission show that the oscillation amplitudes increase…
With recent advances in asteroseismology it is now possible to peer into the cores of red giants, potentially providing a way to study processes such as nuclear burning and mixing through their imprint as sharp structural variations --…
Mixed modes observed in red giants allow for investigation of the stellar interior structures. One important feature in these structures is the buoyancy spike caused by the discontinuity of the chemical gradient left behind during the first…
There is growing observational evidence that the variability of red giants could be caused by excitation of global modes of oscillation. The most recent evidence of such oscillations was reported for alpha UMa by Buzasi et al.(2000). We…
Space-based observations of solar-like oscillations present an opportunity to constrain stellar models using individual mode frequencies. However, current stellar models are inaccurate near the surface, which introduces a systematic…
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…
In oscillating stars, mixed modes have p-mode character in the envelope and g-mode character in the core. They are observed in subgiants and red giants, in which the large density gradient outside the core effectively divides the star into…
The size of convective cores remains uncertain, despite its substantial influence on stellar evolution, and thus on stellar ages. The seismic modeling of young subgiants can be used to obtain indirect constraints on the core structure…
The existence of mixed modes in stars is a marker of stellar evolution. Their detection serves for a better determination of stellar age. The goal of this paper is to identify the dipole modes in an automatic manner without human…
While solar-like oscillations in red giants have been observed at massive scale by the Kepler mission, few features of these oscillation mode frequencies, other than their global properties, have been exploited for stellar characterization.…
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…
Observations of stars other than the Sun are sensitive to oscillations of only low degree. Many are high-order acoustic modes. Acoustic frequencies of main-sequence stars, for example, satisfy a well-known pattern, which some astronomers…
Seismic observations have shown that a number of evolved stars exhibit low-amplitude dipole modes, which are referred to as depressed modes. Recently, these low amplitudes have been attributed to the presence of a strong magnetic field in…
Rotation is an important, yet poorly-modelled phenomenon of stellar structure and evolution. Accurate estimates of internal rotation rates are therefore valuable for constraining stellar evolution models. We aim to assess the accuracy of…
Asteroseismology is able to conduct studies on the interiors of solar-type stars from the analysis of stellar acoustic spectra. However, such an analysis process often has to rely upon subjective choices made throughout. A recurring problem…
With the success of the Kepler and CoRoT missions, the number of stars with detected solar-like oscillations has increased by several orders of magnitude, for the first time we are able to perform large-scale ensemble asteroseismology of…
Asteroseismology is a powerful way of determining stellar parameters and properties of stars like the Sun. However, main-sequence F-type stars exhibit short mode lifetimes relative to their oscillation frequency, resulting in overlapping…
Asteroseismic modelling is a powerful way to derive stellar properties. However, the derived quantities are limited by built-in assumptions used in stellar models. This work presents a detailed characterisation of stellar model…
Acoustic oscillations in stars are sensitive to stellar interiors. Frequency differences between overtone modes -- large separations -- probe stellar density, while differences between low-degree modes -- small separations -- probe the…