Related papers: Angular momentum transfer between oscillations and…

This paper is the second in a series where we examine the generation and filtering of internal gravity waves in stars and the consequences of wave induced transport of angular momentum at various stages of the stellar evolution. Here we…

In the first spectroscopic campaign for a PG 1716 variable (or long-period pulsating subdwarf B star), we succeeded in detecting velocity variations due to g-mode pulsations at a level of 1.0-1.5 km/s.The observations were obtained during…

Realistic stellar models are essential to the forward modelling approach in asteroseismology. For practicality however, certain model assumptions are also required. For example, in the case of subdwarf B stars, one usually starts with…

We consider the excitation of radial and non-radial oscillations in low-mass B stars by the iron-bump opacity mechanism. The results are significant for the interpretation of pulsations in subdwarf B stars, helium-rich subdwarfs and extreme…

Opacity enhancements for stellar interior conditions have been explored to explain observed pulsation frequencies and to extend the pulsation instability region for B-type main-sequence variable stars. For these stars, the pulsations are…

We have performed the first three-dimensional non-linear simulation of the turbulent convective envelope of a rotating 0.8 Msun RGB star using the ASH code. Adopting a global typical rotation rate of a tenth of the solar rate, we have…

We report the transfer of phase structure, and in particular of orbital angular momentum, from near-infrared pump light to blue light generated in a four-wave-mixing process in 85Rb vapour. The intensity and phase profile of the two pump…

In this paper we derive a bound on the rate of change of the gravitational constant G coming from the pulsating white dwarf G117-B15A. This star is a ZZ Ceti pulsator extensively studied with astroseismological techniques for last three…

The observed solar oscillation spectrum is influenced by internal perturbations such as flows and structural asphericities. These features induce splitting of characteristic frequencies and distort the resonant-mode eigenfunctions. Global…

Effects of stellar rotation on adiabatic oscillation frequencies of pressure modes are discussed. Methods to evaluate them are briefly exposed and some of their main results are presented.

Using data from the Gaia satellite's Radial Velocity Spectrometer Data Release 3 (RVS, DR3), we find a new and robust feature in the phase space distribution of halo stars. It is a prominent ridge at constant energy and with angular…

The mixing of material from stellar convective cores into their adjacent radiative layers has been a matter of long-standing debate. Pulsating subdwarf B stars offer excellent conditions to advance our understanding of this problem. In this…

In rapidly rotating stars Coriolis forces and centrifugal deformations modify the properties of oscillations; the Coriolis force is important for low-frequency modes, while the centrifugal deformation affects mainly p-modes. Here, we…

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…

It has been observed that the trajectory of a H2 molecular beam is modified as it passes through a homogeneous magnetic field and an oscillating magnetic field. Based on this observation, this work describes a new method to determine the…

While many intermediate- and high-mass main sequence stars are rapidly and differentially rotating, the effects of rotation on oscillation modes are poorly known. In this communication we present a first study of axisymmetric…

Rotation plays an important role in stellar evolution. However, the mechanisms behind the transport of angular momentum in stars at various stages of their evolution are not well understood. To improve our understanding of these processes,…

A phase transition occurring in the inner core of a neutron star could be associated to a density discontinuity that would affect the frequency spectrum of the non-radial oscillation modes in two ways. Firstly, it would produce a softening…

Stellar rotation affects the transport of chemical elements and angular momentum and is therefore a key process during stellar evolution, which is still not fully understood. This is especially true for massive stars, which are important…

During the course of an ongoing CCD monitoring program to investigate low-level light variations in subdwarf B (sdB) stars, we have serendipitously discovered a new class of low amplitude, multimode sdB pulsators with periods of the order…