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Despite more and more observational data, stellar acoustic oscillation modes are not well understood as soon as rotation cannot be treated perturbatively. In a way similar to semiclassical theory in quantum physics, we use acoustic ray…

Solar and Stellar Astrophysics · Physics 2011-09-16 M. Pasek , B. Georgeot , F. Lignieres , D. R. Reese

The region in the HR-diagram where the main sequence intersects the classical instability strip hosts A- and F-type stars exhibiting a rich variety of physical phenomena, such as pulsations on various time scales and chemical peculiarities.…

Solar and Stellar Astrophysics · Physics 2009-01-22 S. Hekker , Y. Frémat , P. Lampens , P. De Cat

Combination frequencies are observed in the Fourier spectra of pulsating DA and DB white dwarfs. They appear at sums and differences of frequencies associated with the stellar gravity-modes. Brickhill (1992) proposed that the combination…

Astrophysics · Physics 2009-10-31 Yanqin Wu

We briefly review progress in developing a pathway to nonlinear astereoseismology, both from theoretical and observational aspects. As predicted by the theory of weak nonlinear interactions between resonant modes, their amplitude and…

Solar and Stellar Astrophysics · Physics 2023-02-07 Weikai Zong , Stéphane Charpinet , Gérard Vauclair , Jian-Ning Fu , Xiao-Yu Ma

Low amplitude is the defining characteristic of solar-like oscillations. The space projects $Kepler$ and $CoRoT$ give us a great opportunity to successfully detect such oscillations in numerous targets. Achievements of asteroseismology…

Solar and Stellar Astrophysics · Physics 2015-06-19 M. Yıldız , Z. Çelik Orhan , Ç. Aksoy , S. Ok

There are many Slowly Pulsating B (SPB) stars and gamma Dor stars in the Kepler Mission data set. The light curves of these pulsating stars have been classified phenomenologically into stars with symmetric light curves and with asymmetric…

Solar and Stellar Astrophysics · Physics 2015-05-27 Donald W. Kurtz , Hiromoto Shibahashi , Simon J. Murphy , Timothy R. Bedding , Dominic M. Bowman

Astrophysical objects frequently exhibit some irregularities or complex behaviour in their light curves. We focus primarily on hot stars, where both radial and non-radial pulsations are observed. One of the primary research goals is to…

Solar and Stellar Astrophysics · Physics 2009-11-13 V. Votruba , P. Koubský , D. Korčáková , F. Hroch

Determining the equation of state of matter at nuclear density and hence the structure of neutron stars has been a riddle for decades. We show how the imminent detection of gravitational waves from merging neutron star binaries can be used…

General Relativity and Quantum Cosmology · Physics 2014-09-05 Kentaro Takami , Luciano Rezzolla , Luca Baiotti

Asteroseismology is a powerful tool for probing the internal structures of stars by using their natural pulsation frequencies. It relies on identifying sequences of pulsation modes that can be compared with theoretical models, which has…

Asteroseismology has opened a window on the internal physics of thousands of stars, by relating oscillation spectra properties to the internal physics of stars. Mode identification, namely the process of associating a measured oscillation…

Solar and Stellar Astrophysics · Physics 2022-09-21 Giovanni Marcello Mirouh

Anomalies drive scientific discovery -- they are associated with the cutting edge of the research frontier, and thus typically exploit data in the low signal-to-noise regime. In astronomy, the prevalence of systematics --- both "known…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-16 Hiranya V. Peiris

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…

Solar and Stellar Astrophysics · Physics 2015-06-12 A. R. G. Santos , M. S. Cunha , J. J. G. Lima

Asteroseismology has become an indispensable method for measuring stellar ages and radii, while binary systems remain the most prevalent tool for determining stellar masses. The synergy of the two, namely pulsating stars in binary systems,…

Solar and Stellar Astrophysics · Physics 2024-11-12 Simon J. Murphy

The investigation of the pulsation properties of pre-main-sequence intermediate-mass stars is a promising tool to evaluate the intrinsic properties of these stars and to constrain current evolutionary models. Many new candidates of this…

The majority of the well-studied Delta Scuti stars show frequency pairs in the power spectra with frequency separations less than 0.06 c/d(0.7 microHz) as well as amplitude variability. We examine the interpretation in terms of separate…

Astrophysics · Physics 2009-11-07 M. Breger , K. M. Bischof

Asteroseismology involves using the resonant frequencies of a star to infer details about its internal structure and evolutionary state. Oscillation frequencies are most useful when accompanied by accurate measurements of the more…

Astrophysics · Physics 2007-05-23 Timothy R. Bedding

Space missions have produced an incredibly large database on pulsating stars. The light curves via the frequency content contain a detailed description of each star. The critical point is the identification of modes, especially in the…

Solar and Stellar Astrophysics · Physics 2013-08-27 M. Paparó , J. M. Benkő

In the analysis of variable stars, the problem of sampling is central. This article focusses on the determination of the Nyquist frequency. It is well defined in the case of regular sampling. However, the time series of variable stars…

Astrophysics · Physics 2009-10-30 L. Eyer , P. Bartholdi

Some pulsating stars are good clocks. When they are found in binary stars, the frequencies of their luminosity variations are modulated by the Doppler effect caused by orbital motion. For each pulsation frequency this manifests itself as a…

Solar and Stellar Astrophysics · Physics 2015-06-04 Hiromoto Shibahashi , Donald W. Kurtz

The unprecedented light curves of the Kepler space telescope document how the brightness of some stars pulsates at primary and secondary frequencies whose ratios are near the golden mean, the most irrational number. A nonlinear dynamical…

Chaotic Dynamics · Physics 2015-02-05 John F. Lindner , Vivek Kohar , Behnam Kia , Michael Hippke , John G. Learned , William L. Ditto