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Related papers: Stellarators close to quasisymmetry

200 papers

Radial and nonradial oscillations offer the opportunity to investigate the interior properties of stars. We use 2D stellar models and a 2D finite difference integration of the linearized pulsation equations to calculate non-radial…

Astrophysics · Physics 2009-11-13 C. C. Lovekin , R. G. Deupree

While stellar rotation periods $P_\mathrm{rot}$ may be measured from broadband photometry, the photometric modulation becomes harder to detect for slower rotators, which could bias measurements of the long-period tail of the…

Solar and Stellar Astrophysics · Physics 2021-12-22 Kento Masuda , Erik A. Petigura , Oliver J. Hall

The high-energy emission from low-mass stars is mediated by the magnetic dynamo. Although the mechanisms by which fully convective stars generate large-scale magnetic fields are not well understood, it is clear that, as for solar-type…

Solar and Stellar Astrophysics · Physics 2017-01-11 Elisabeth R. Newton , Jonathan Irwin , David Charbonneau , Perry Berlind , Michael L. Calkins , Jessica Mink

Many pulsars are formed with a binary companion from which they can accrete matter. Torque exerted by accreting matter can cause the pulsar spin to increase or decrease, and over long times, an equilibrium spin rate is achieved. Application…

Solar and Stellar Astrophysics · Physics 2014-01-03 Wynn C. G. Ho , H. Klus , M. J. Coe , Nils Andersson

In this work, we develop a perturbation theory to analyze resonant states near a bound state in the continuum (BIC) in photonic crystal slabs. The theory allows us to rigorously determine the asymptotic behavior of $Q$-factor and the…

Optics · Physics 2024-12-10 Nan Zhang , Ya Yan Lu

We present a sample of 824 solar and late-type stars with X-ray luminosities and rotation periods. This is used to study the relationship between rotation and stellar activity and derive a new estimate of the convective turnover time. From…

Solar and Stellar Astrophysics · Physics 2015-05-30 Nicholas J. Wright , Jeremy J. Drake , Eric E. Mamajek , Gregory W. Henry

In this paper we compute general-relativistic polytropic models simulating rigidly rotating, pulsating neutron stars. These relativistic compact objects, with a radius of $\sim 10 \, \mathrm{km}$ and mass between $\sim 1.4$ and $3.2$ solar…

General Relativity and Quantum Cosmology · Physics 2014-10-14 Vassilis Geroyannis , Eleftheria Tzelati

We investigate the effect of new stellar models, which take rotation into account, computed for a metallicity Z = 10^{-8} on the chemical evolution of the earliest phases of the Milky Way. These models are computed under the assumption that…

Astrophysics · Physics 2009-11-11 C. Chiappini , R. Hirschi , G. Meynet , S. Ekström , A. Maeder , F. Matteucci

Neutron stars are not observed to spin faster than about half their breakup rate. This limiting rotational frequency may be related to the strength of their crusts. As a star spins up from accretion, centrifugal forces stress the crust. We…

High Energy Astrophysical Phenomena · Physics 2024-12-17 J. A. Morales , C. J. Horowitz

Raytracing computations for light emitted from the surface of a rapidly rotating neutron star are carried out in order to construct light curves for accreting millisecond pulsars. These calculations are for realistic models of rapidly…

Astrophysics · Physics 2007-05-23 D. Leahy , S. Morsink , C. Cadeau

Many stars, including those in binary or multiple systems, exhibit modified rotational evolution due to tidal interactions. While magnetic braking slows rotation in single stars, close binaries experience synchronization from tidal forces,…

Solar and Stellar Astrophysics · Physics 2025-05-19 Ilay Kamai , Hagai B. Perets

There is currently no agreed-upon methodology for characterizing a stellarator magnetic field geometry, and yet modern stellarator designs routinely attain high levels of magnetic-field quasi-symmetry through careful flux-surface shaping.…

Plasma Physics · Physics 2026-01-01 M. J. Gerard , M. J. Pueschel , S. Stewart , H. O. M. Hillebrecht , B. Geiger

Microinstabilities exhibit a rich variety of behavior in stellarators due to the many degrees of freedom in the magnetic geometry. It has recently been found that certain stellarators (quasi-isodynamic ones with maximum-$J$ geometry) are…

Plasma Physics · Physics 2015-06-17 J. H. E. Proll , P. Xanthopoulos , P. Helander

We calculate the rotational broadening in the observed thermal spectra of neutron stars spinning at moderate rates in the Hartle-Thorne approximation. These calculations accurately account for the effects of the second-order Doppler boosts…

High Energy Astrophysical Phenomena · Physics 2016-08-17 Michi Baubock , Feryal Ozel , Dimitrios Psaltis , Sharon M. Morsink

We show that r-mode oscillations distort the magnetic fields of neutron stars and that their occurrence is likely to be limited by this interaction. If the field is gtrsim 10^{16} (Omega/Omega_B) G, where Omega and Omega_B are the angular…

Astrophysics · Physics 2009-10-31 Luciano Rezzolla , Frederick K. Lamb , Stuart L. Shapiro

For $^{12}$C and $^{16}$O, rotating models predict in general enhanced yields. At high metallicity, the carbon and oxygen yields from the very high mass stars, which go through a WR phase, are little affected by rotation. For $^{14}$N,…

Astrophysics · Physics 2007-05-23 Georges Meynet , Andre Maeder , Raphael Hirschi

Nine stellarator configurations, three quasiaxisymmetric, three quasihelically symmetric and three non-quasisymmetric are scaled to ARIES-CS size and analyzed for energetic particle content. The best performing configurations with regard to…

Plasma Physics · Physics 2021-10-27 A Bader , D T Anderson , M Drevlak , B J Faber , C C Hegna , S Henneberg , M Landreman , J C Schmitt , Y Suzuki , A Ware

Tens of thousands of rotation periods have been measured in the Kepler fields, including a substantial fraction of rapid rotators. We use Gaia parallaxes to distinguish photometric binaries (PBs) from single stars on the unevolved lower…

Solar and Stellar Astrophysics · Physics 2019-02-07 Gregory V. A. Simonian , Marc H. Pinsonneault , Donald M. Terndrup

The Sun and solar-type stars exhibit irregular cyclic variations in their magnetic activity over long time scales. To understand this irregularity, we employed the flux transport dynamo models to investigate the behavior of one solar mass…

Solar and Stellar Astrophysics · Physics 2024-12-25 Vindya Vashishth

Superradiance in black holes is well-understood but a general treatment for superradiance in stars has until now been lacking. This is surprising given the ease with which we can observe isolated neutron stars and the array of signatures…

High Energy Physics - Phenomenology · Physics 2022-12-14 Francesca Chadha-Day , Björn Garbrecht , Jamie McDonald