Related papers: Some musings on erythrogigantoacoustics
Asteroseismic measurements enable inferences of the underlying stellar structure, such as the density and the speed of sound at various points within the interior of the star. This provides an opportunity to test stellar evolution theory by…
Turbulent processes in the convective envelopes of the sun and stars have been shown to be a source of internal acoustic excitations. In single stars, acoustic waves having frequencies below a certain cutoff frequency propagate nearly…
The space-borne missions CoRoT and Kepler have provided a large amount of precise photometric data. Among the stars observed, red giants show a rich oscillation pattern that allows their precise characterization. Long-duration observations…
Asteroseismic inferences of main-sequence solar-like oscillators often rely on best-fit models. However, these models cannot fully reproduce the observed mode frequencies, suggesting that the internal structure of the model does not fully…
An understanding of stellar acoustic oscillations is attempted, using the local wave concept in semi-analytical calculations. The local homogeneity approximation allows to obtain simplified equations that can nevertheless describe the wave…
The physical structures of the outer atmospheres of red giants are not known. They are certainly complex and a range of recent observations are showing that we need to embrace to non-classical atmosphere models to interpret these regions.…
Asteroseismology, i.e. the study of the internal structures of stars via their global oscillations, is a valuable tool to obtain stellar parameters such as mass, radius, surface gravity and mean density. These parameters can be obtained…
Acoustic modes of oscillation are affected by stellar activity, however it is unclear how starspots contribute to these changes. Here we investigate the nonmagnetic effects of starspots on global modes with angular degree $\ell \leq 2$ in…
Michelson phase and Hanbury Brown-Twiss intensity stellar interferometry require expressions for the first- and second-order correlation functions, respectively, of the fields radiated by stars in terms of their diameters and measured…
Red Giant stars host solar-like oscillations which have mixed character, being sensitive to conditions both in the outer convection zone and deep within the interior. The properties of these modes are sensitive to both core rotation and…
The asteroseismology of rapidly rotating pulsating stars is hindered by our poor knowledge of the effect of the rotation on the oscillation properties. Here we present an asymptotic analysis of high-frequency acoustic modes in rapidly…
An extensive survey of gravitational-wave modes for uniform density stars is presented. The study covers stars ranging in compactness from $R/M=100$ to the limit of stability in general relativity: $R/M = 9/4$. We establish that polar and…
We present estimates of the amplitudes of intrinsically stable stochastically excited radial oscillations in stars near the main sequence. The amplitudes are determined by the balance between acoustical energy generation by turbulent…
We investigated the radial and non-radial fundamental ($f$) mode oscillations of self-bound (quark) stars obtained after employing the Vector MIT (vMIT) bag model. Within this model, we computed the equation of state for strange quark…
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…
Analysis of f-mode frequencies has provided a measure of the radius of the Sun which is lower, by a few hundredths per cent, than the photospheric radius determined by direct optical measurement. Part of this difference can be understood by…
It has been established earlier that sharp features like the base of the convective zone or the second helium ionisation zone inside a star give rise to sinusoidal oscillations in the frequencies of pulsation. The acoustic depth of such…
It is notoriously difficult to measure the winds of solar-type stars. Traditional spectroscopic and radio continuum techniques are sensitive to mass loss rates at least two to three orders of magnitude stronger than the Sun's relatively…
State-of-the-art stellar structure and evolution codes fail to adequately describe turbulent convection. For stars with convective envelopes, such as red giants, this leads to an incomplete depiction of the surface layers. As a result, the…
The eigenfrequency problem of fundamental vibrational mode in a highly inhomogeneous star, modeled by self-gravitating mass of viscous liquid with singular density at the center, is considered in juxtaposition with that for Kelvin…