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We model the stochastic excitation of acoustic modes in solar-like pulsators taking into account the action of differential rotation. We derive the theoretical formalism for the stochastic excitation with differential rotation and make use…

Solar and Stellar Astrophysics · Physics 2024-10-31 Gabriel Biscarrat , Leïla Bessila , Stéphane Mathis

A new method is presented here for evaluating approximately the pulsation modes of relativistic stellar models. This approximation relies on the fact that gravitational radiation influences these modes only on timescales that are much…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Lee Lindblom , Gregory Mendell , James R. Ipser

Detecting and understanding rotation in stellar interiors is nowadays one of the unsolved problems in stellar physics. Asteroseismology has been able to provide insights on rotation for the Sun, solar-like stars, and compact objects like…

Solar and Stellar Astrophysics · Physics 2021-06-24 A. Ramón-Ballesta , A. García Hernández , J. C. Suárez , J. R. Rodón , J. Pascual-Granado , R. Garrido

We study acoustic oscillations (eigenfrequencies, velocity distributions, damping times) of normal crusts of strange stars. These oscillations are very specific because of huge density jump at the interface between the normal crust and the…

Astrophysics · Physics 2008-11-26 A. I. Chugunov

After a brief recall of the main impacts of stellar rotation on the structure and the evolution of stars, four topics are addressed: 1) the links between magnetic fields and rotation; 2) the impact of rotation on the age determination of…

To obtain the most accurate pulse arrival times from radio pulsars, it is necessary to correct or mitigate the effects of the propagation of radio waves through the warm and ionised interstellar medium. We examine both the strength of…

Instrumentation and Methods for Astrophysics · Physics 2016-11-15 R. M. Shannon , J. M. Cordes

Recent dramatic improvements in the modeling of abundance evolution due to diffusion in A stars have been achieved with the help of monochromatic opacity tables from the OPAL group. An important result in the context of stellar pulsations…

Astrophysics · Physics 2007-05-23 S. Turcotte , J. Richer , G. Michaud , J. Christensen-Dalsgaard

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

Quasi-periodic X-ray brightness oscillations (QPOs) with frequencies around a kilohertz have now been discovered in more than a dozen neutron stars in low-mass X-ray binary systems using the Rossi X-ray Timing Explorer. There is strong…

Astrophysics · Physics 2009-10-30 M. Coleman Miller , Frederick K. Lamb , Gregory B. Cook

Using weakly non-linear theory of oscillation, we estimate the amplitudes of low frequency modes in a slowly pulsating B (SPB) star, taking account of the effects of rotation on the modes. Applying the formulation by Schenk et al (2002), we…

Solar and Stellar Astrophysics · Physics 2015-06-03 Umin Lee

We analyze the frequency dependence of the dispersion measure (DM), the column density of free electrons to a pulsar, caused by multipath scattering from small scale electron-density fluctuations. The DM is slightly different along each…

Instrumentation and Methods for Astrophysics · Physics 2016-01-21 J. M. Cordes , R. M. Shannon , D. R. Stinebring

At second order in perturbation theory, the $r$-modes of uniformly rotating stars include an axisymmetric part that can be identified with differential rotation of the background star. If one does not include radiation-reaction, the…

High Energy Astrophysical Phenomena · Physics 2018-03-07 John L. Friedman , Lee Lindblom , Keith H. Lockitch

In a second-order r-mode theory, S'a & Tom'e found that the r-mode oscillation in neutron stars (NSs) could induce stellar differential rotation, which leads to a saturation state of the oscillation spontaneously. Based on a consideration…

Solar and Stellar Astrophysics · Physics 2009-09-28 Yun-Wei Yu , Xiao-Feng Cao , Xiao-Ping Zheng

One of the greatest challenges in interpreting the pulsations of rapidly rotating stars is mode identification, i.e. correctly matching theoretical modes to observed pulsation frequencies. Indeed, the latest observations as well as current…

Solar and Stellar Astrophysics · Physics 2017-11-08 Daniel Roy Reese , Marc-Antoine Dupret , Michel Rieutord

The angular momentum (AM) evolution of stellar interiors, along with the resulting rotation rates of stellar remnants, remains poorly understood. Asteroseismic measurements of red giant stars reveal that their cores rotate much faster than…

Solar and Stellar Astrophysics · Physics 2019-03-08 Jim Fuller , Anthony L. Piro , Adam S. Jermyn

The spin-up of a neutron star crucially depends on the maximum orbital frequency around it, as do a host of other high energy accretion phenomena in low mass X-ray binaries, including quasi-periodic oscillations (QPOs) in the X-ray flux. We…

Astrophysics · Physics 2007-05-23 D. Gondek-Rosinska , W. Kluzniak

In this work the latitude dependent stellar spot rotation is investigated based on dynamo models. The maps of the magnetic pressure at the surface from the dynamo calculations are treated similarly to the temperature maps obtained using…

Solar and Stellar Astrophysics · Physics 2015-05-28 H. Korhonen , D. Elstner

We examine the potential of asteroseismology for exploring the internal rotation of white dwarf stars. Data from global observing campaigns have revealed a wealth of frequencies, some of which show the signature of rotational splitting.…

Astrophysics · Physics 2009-10-31 Steven D. Kawaler , Takashi Sekii , Douglas Gough

In the solar convection zone, rotation couples with intensely turbulent convection to build global-scale flows of differential rotation and meridional circulation. Our sun must have rotated more rapidly in its past, as is suggested by…

Many recent observations give restrictions to the equation of state (EOS) for high-density matter. Theoretical studies are needed to try to elucidate these EOSs at high density and/or temperature. With the many known rapidly rotating…

High Energy Astrophysical Phenomena · Physics 2018-02-14 Tomoki Endo