Unidirectional motion of magnetic domain walls: the experiment and numerical simulation

Pamyatnykh, L. A.; Lysov, M. S.; Pamyatnykh, Sergey E.; Mekhonoshin, D. S.; Agafonov, L. Y.; Shmatov, G. A.

doi:10.1088/1742-6596/1389/1/012001

Cited by 5 publications

(4 citation statements)

References 9 publications

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“…In the frequency spectra of the evolutionary stellar models with a mass of 1.8 M , Pamyatnykh (2000) and Dupret et al (2005) have reported the presence of low order unstable radial modes where consecutive modes are separated with almost an equivalent distance in frequency Fig. 1 of Pamyatnykh 2000 andDupret et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Study of pulsational instabilities in models of δ Scuti pulsators discovered under the Nainital-Cape Survey

Yadav¹

2019

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Under the Nainital-Cape Survey, eight Scuti type pulsators have been discovered with the pulsation periods in the range of several minutes to few hours. In order to understand these observed pulsational variabilities, we have performed non-adiabatic linear stability analyses of these stars having mass in the range of 1 to 3 Mʘ. Several low order pressure modes (p-modes) are found to be unstable where the pulsation pe-riods associated with these unstable modes are in good agreement with the observed periods. Particularly for HD 118660, HD 113878, HD 102480, HD 98851, and HD 25515, we demonstrate that the observed variabilities can be explained with the low order radial p-mode pulsations.

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Section: Discussionmentioning

confidence: 99%

Study of pulsational instabilities in models of δ Scuti pulsators discovered under the Nainital-Cape Survey

Yadav¹

2019

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“…In the frequency spectra of the evolutionary stellar models with a mass of 1.8 M ⊙ , Pamyatnykh (2000) and Dupret et al (2005) have reported the presence of low order unstable radial modes where consecutive modes are separated with almost an equivalent distance in frequency (e.g., Fig. 1 of Pamyatnykh 2000 andDupret et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Study of pulsational instabilities in models of $δ\,$Scuti pulsators discovered under the Nainital-Cape Survey

Yadav

2019

Preprint

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Under the Nainital-Cape Survey, eight δ Scuti type pulsators have been discovered with the pulsation periods in the range of several minutes to few hours. In order to understand these observed pulsational variabilities, we have performed non-adiabatic linear stability analyses in models of these stars having mass in the range of 1 to 3 M ⊙ . Several low order p-modes are found to be unstable where the pulsation periods associated with these unstable modes are in good agreement with the observed periods. Particularly for HD 118660, HD 113878, HD 102480, HD 98851, and HD 25515, we demonstrate that the observed variabilities can be explained with the low order radial p-mode pulsations.

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“…F-type stars can show four types of pulsations: (i) δ Scutitype p-modes driven by the κ-mechanism acting in the He ii ionisation zone (Pamyatnykh et al 2000), (ii) γ Doradus-type g-modes that are caused by the convective flux blocking mechanism (Guzik et al 2000), (iii) gravito-inertial modes or Rossby (r) modes where the Coriolis force is the restoring force (Saio et al 2018), and (iv) stochastic solar-like oscillations for which pressure is the restoring force (e.g. Kjeldsen & Bedding 1995).…”

Section: Introductionmentioning

confidence: 99%

β Cas: The first δ Scuti star with a dynamo magnetic field

Zwintz

Neiner

Kochukhov

et al. 2020

A&A

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Context. F-type stars are characterised by several physical processes such as different pulsation mechanisms, rotation, convection, diffusion, and magnetic fields. The rapidly rotating δ Scuti star β Cas can be considered as a benchmark star to study the interaction of several of these effects. Aims. We investigate the pulsational and magnetic field properties of β Cas. We also determine the star’s apparent fundamental parameters and chemical abundances. Methods. Based on photometric time series obtained from three different space missions (BRITE-Constellation, SMEI, and TESS), we conduct a frequency analysis and investigate the stability of the pulsation amplitudes over four years of observations. We investigate the presence of a magnetic field and its properties using spectropolarimetric observations taken with the Narval instrument by applying the least-squares deconvolution and Zeeman-Doppler imaging techniques. Results. The star β Cas shows only three independent p-mode frequencies down to the few ppm-level; its highest amplitude frequency is suggested to be an n = 3, ℓ = 2, m = 0 mode. Its magnetic field structure is quite complex and almost certainly of a dynamo origin. The atmosphere of β Cas is slightly deficient in iron peak elements and slightly overabundant in C, O, and heavier elements. Conclusions. Atypically for δ Scuti stars, we can only detect three pulsation modes down to exceptionally low noise levels for β Cas. The star is also one of very few δ Scuti pulsators known to date to show a measurable magnetic field and the first δ Scuti star with a dynamo magnetic field. These characteristics make β Cas an interesting target for future studies of dynamo processes in the thin convective envelopes of F-type stars, the transition region between fossil and dynamo fields, and the interaction between pulsations and magnetic field.

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Unidirectional motion of magnetic domain walls: the experiment and numerical simulation

Cited by 5 publications

References 9 publications

Study of pulsational instabilities in models of δ Scuti pulsators discovered under the Nainital-Cape Survey

Study of pulsational instabilities in models of δ Scuti pulsators discovered under the Nainital-Cape Survey

Study of pulsational instabilities in models of $δ\,$Scuti pulsators discovered under the Nainital-Cape Survey

β Cas: The first δ Scuti star with a dynamo magnetic field

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