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We review the main results obtained from our seismic studies of B-type main sequence pulsators, based on the ground-based, MOST, Kepler and BRITE observations. Important constraints on stellar opacities, convective overshooting and rotation…

Solar and Stellar Astrophysics · Physics 2018-12-04 Jadwiga Daszynska-Daszkiewicz , Przemysław Walczak , Wojciech Szewczuk , Alosha Pamyatnykh

Massive main-sequence stars have convective cores and radiative envelopes, but also sub-surface convection zones caused by partial ionisation. However, the convective properties depend on opacity and a star's metallicity. Non-rotating 1D…

Solar and Stellar Astrophysics · Physics 2024-11-21 Dominic M. Bowman , Pieterjan Van Daele , Mathias Michielsen , Timothy Van Reeth

We present an asymptotic theory that describes regular frequency spacings of pressure modes in rapidly rotating stars. We use an asymptotic method based on an approximate solution of the pressure wave equation constructed from a stable…

Solar and Stellar Astrophysics · Physics 2012-09-27 Michael Pasek , François Lignières , Bertrand Georgeot , Daniel R. Reese

We use the traditional approximation to describe oscillations with frequencies comparable to the angular rotation rate. Validity of this approximation in application to main-sequence B stars is discussed. Numerical results regarding mode…

Astrophysics · Physics 2008-11-26 W. A. Dziembowski , J. Daszynska-Daszkiewicz , A. A. Pamyatnykh

The composition and equation of state (EoS) of dense matter relevant to compact stars are quite inconclusive. However, certain observational constraints on the structural properties of compact stars help us constrain the EoS to a fair…

High Energy Physics - Phenomenology · Physics 2025-04-22 Atanu Guha , Debashree Sen , Chang Ho Hyun

We investigate strong nonlinear damping effects which occur during high amplitude oscillations of neutron stars, and the gravitational waves they produce. For this, we use a general relativistic nonlinear hydrodynamics code in conjunction…

General Relativity and Quantum Cosmology · Physics 2011-10-06 Wolfgang Kastaun , Beatrix Willburger , Kostas D. Kokkotas

We describe sophisticated new Bayesian analysis methods that make it possible to estimate quickly the masses and radii of rapidly rotating, oblate neutron stars by fitting oblate-star waveform models to energy-resolved observations of the…

High Energy Astrophysical Phenomena · Physics 2015-08-06 M. Coleman Miller , Frederick K. Lamb

We perform Large eddy simulations of turbulent compressible convection in stellar-type convection zones by solving the Navi\'{e}r-Stokes equations in three dimensions. We estimate the extent of penetration into the stable layer above a…

Astrophysics · Physics 2009-06-23 Partha S. Pal , Harinder P. Singh , Kwing L. Chan , M. P. Srivastava

We have studied the stability of low degree $g$-modes in uniformly rotating B-type stars, taking into account the effects of the Coriolis force and the rotational deformation. From an analysis treating rotation frequency as a small…

Solar and Stellar Astrophysics · Physics 2015-05-20 Aprilia , Umin Lee , Hideyuki Saio

We discuss the properties of pulsations in the OGLE Small Amplitude Red Giants (OSARGs) in the Large Magellanic Cloud (LMC). We consider stars below the red-giant tip in this paper. They are multi-periodic and form three sequences in the…

Solar and Stellar Astrophysics · Physics 2015-06-15 Masaki Takayama , Hideyuki Saio , Yoshifusa Ita

Solar-like oscillations are expected to be excited in stars of up to about 1.6 solar masses. Most of these stars will have convective cores during their Main-sequence evolution. At the edges of these convective cores there is a rapid…

Solar and Stellar Astrophysics · Physics 2015-05-19 Margarida S. Cunha , Isa M. Brandão

Massive stars are progenitors of supernovae, neutron stars and black holes. During the hydrogen-core burning phase their convective cores are the prime drivers of their evolution, but inferences of core masses are subject to unconstrained…

We investigate the pulsational stability of massive (M >~ 120 Msun) main sequence stars of a range of metallicities, including primordial, Population III stars. We include a formulation of convective damping motivated by numerical…

Solar and Stellar Astrophysics · Physics 2015-06-04 Joshua H. Shiode , Eliot Quataert , Phil Arras

Using CCD photometry obtained by the EROS collaboration in 1991-1993, we have discovered an LMC variable star with a light curve that is oscillating with a mean period of $\sim 14$ days and an amplitude of $\sim$ 0.3 mag. The oscillations…

Astrophysics · Physics 2007-05-23 J. P. Beaulieu , R. Buchler , M. J. Goupil , Z. Kollath

We present a study of the Rayleigh-Taylor unstable regime of accretion onto rotating magnetized stars in a set of high grid resolution three-dimensional (3D) magnetohydrodynamic (MHD) simulations performed in low-viscosity discs. We find…

Solar and Stellar Astrophysics · Physics 2016-05-18 A. A. Blinova , M. M. Romanova , R. V. E. Lovelace

We find that low-degree low-order g-modes become unstable in metal-poor low-mass stars due to the $\varepsilon$-mechanism of the pp-chain. Since the outer convection zone of these stars is limited only to the very outer layers, the…

Solar and Stellar Astrophysics · Physics 2015-06-04 Takafumi Sonoi , Hiromoto Shibahashi

We find that the observed pressure-mode rotational splittings of slowly/moderately rotating Delta Scuti stars and Beta Cephei stars mostly have a positive asymmetry. That is, the left frequency spacing is larger than the right spacing in…

Solar and Stellar Astrophysics · Physics 2024-06-25 Zhao Guo , Timothy R. Bedding , A. A. Pamyatnykh , Donald W. Kurtz , Gang Li , Anuj Gautam , Simon J. Murphy , Conny Aerts

We have studied a sample containing about 6000 OB stars with proper motions and trigonometric parallaxes from the Gaia DR2 catalogue. The following parameters of the angular velocity of Galactic rotation have been found:…

Astrophysics of Galaxies · Physics 2019-06-26 V. V. Bobylev , A. T. Bajkova

We examine the severe disagreement between the number of predicted and observed pulsation modes for Delta Scuti stars. The selection of nonradial modes trapped in the outer envelope is considered on the basis of kinetic energy arguments.…

Astrophysics · Physics 2007-05-23 M. Breger , A. A. Pamyatnykh

We investigate inertial mode oscillations of slowly and uniformly rotating, isentropic, Newtonian stars. Inertial mode oscillations are induced by the Coriolis force due to the star's rotation, and their characteristic frequencies are…

Astrophysics · Physics 2016-08-30 Shijun Yoshida , Umin Lee