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While long period variables (LPVs) have been extensively investigated, especially with MACHO and OGLE data for the Magellanic Clouds, there still exist open questions in their pulsations regarding the excitation mechanisms, radial order and…

Solar and Stellar Astrophysics · Physics 2020-02-05 Jie Yu , Timothy R. Bedding , Dennis Stello , Daniel Huber , Douglas L. Compton , Laurent Gizon , Saskia Hekker

There is growing evidence, based on both X-ray and radio observations of isolated neutron stars, that besides the large--scale (dipolar) magnetic field, which determines the pulsar spin--down behaviour, small--scale poloidal field…

Astrophysics · Physics 2009-11-10 U. Geppert , M. Rheinhardt , J. Gil

HD189733 is an active K dwarf that is, with its transiting hot Jupiter, among the most studied exoplanetary systems. In this first paper of the Multiwavelength Observations of an eVaporating Exoplanet and its Star (MOVES) program, we…

Certain multi-wavelength observations of neutron stars, such as intermittent radio emissions from rotation-powered pulsars beyond the pair-cascade death line, the pulse profile of the magnetar SGR 1900+14 after its 1998 August 27 giant…

High Energy Astrophysical Phenomena · Physics 2013-07-19 Alpha Mastrano , Paul D. Lasky , Andrew Melatos

We studied possible evolution of the rotational period and the magnetic field of the X-ray source RX J0720.4-3125 assuming this source to be an isolated neutron star accreting interstellar medium. Magnetic field of the source is estimated…

Astrophysics · Physics 2009-10-30 D. Yu. Konenkov , S. B. Popov

Large-scale magnetic fields at the surface of massive stars do not only influence the outer-most layers of the star, but also have consequences for the deep interior, only observationally accessible through asteroseismology. We performed a…

Solar and Stellar Astrophysics · Physics 2017-09-20 B. Buysschaert , C. Neiner , M. Briquet , C. Aerts

The late-B magnetic chemically peculiar star CU Vir is one of the fastest rotators among the intermediate-mass stars with strong fossil magnetic fields. It shows a prominent rotational modulation of the spectral energy distribution and…

Solar and Stellar Astrophysics · Physics 2014-05-21 O. Kochukhov , T. Lueftinger , C. Neiner , E. Alecian

The observed long-term spin-down evolution of isolated radio pulsars cannot be explained by the standard magnetic dipole radiation with a constant braking torque. However how and why the torque varies still remains controversial, which is…

Solar and Stellar Astrophysics · Physics 2015-06-18 Yi Xie , Shuang-Nan Zhang

Relativistic stars are endowed with intense electromagnetic fields but are also subject to oscillations of various types. We here investigate the impact that oscillations have on the electric and magnetic fields external to a relativistic…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Luciano Rezzolla , Bobomurat J. Ahmedov

Many magnetic white dwarfs exhibit a polarised spectrum that periodically varies as the star rotates because the magnetic field is not symmetric about the rotation axis. In this work, we report the discovery that while weakly magnetic white…

Solar and Stellar Astrophysics · Physics 2024-11-18 S. Bagnulo , J. D. Landstreet

The problem of the stability of magnetic fields in stars has a long history and has been investigated in detail in perturbation theory. Here we consider the nonlinear evolution of a non-rotating neutron star with a purely poloidal magnetic…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Riccardo Ciolfi , Samuel K. Lander , Gian Mario Manca , Luciano Rezzolla

We present here spectropolarimetric observations of the RS CVn system HR 1099 (V711 Tau) secured from 1998 February to 2002 January with the spectropolarimeter MuSiCoS at the Telescope Bernard Lyot (Observatoire du Pic du Midi, France). We…

Discovering exoplanets orbiting young Suns can provide insight into the formation and early evolution of our own solar system, but the extreme magnetic activity of young stars obfuscates exoplanet detection. Here we monitor the long-term…

Solar and Stellar Astrophysics · Physics 2024-01-24 E. L. Brown , S. C. Marsden , S. V. Jeffers , A. Heitzmann , J. R. Barnes , C. P. Folsom

Spectropolarimetric observations show that many low-mass stars possess large-scale poloidal magnetic fields with considerable dipole component, which in some cases exhibit temporal dynamics - cycles or reversals. Although it is widely…

Solar and Stellar Astrophysics · Physics 2025-07-02 Anna Guseva , Ludovic Petitdemange , Charly Pinçon

Most studies of the pulsar magnetosphere have assumed a pure magnetic dipole in flat spacetime. However, recent work suggests that the effects of general relativity are in fact of vital importance and that realistic pulsar magnetic fields…

High Energy Astrophysical Phenomena · Physics 2016-12-21 Samuel E. Gralla , Alexandru Lupsasca , Alexander Philippov

Recent asteroseismic analyses have revealed the presence of strong (B $\gtrsim 10^5$ G) magnetic fields in the cores of many red giant stars. Here, we examine the implications of these results for the evolution of stellar magnetic fields,…

Solar and Stellar Astrophysics · Physics 2016-06-15 Matteo Cantiello , Jim Fuller , Lars Bildsten

Strong magnetic fields are observed in a substantial fraction of upper main sequence stars and white dwarfs. Many such stars are observed to exhibit photometric modulations as the magnetic poles rotate in and out of view, which could be a…

Solar and Stellar Astrophysics · Physics 2023-02-22 Jim Fuller , Stephane Mathis

Within the context of the "B fields in OB stars (BOB)" collaboration, we used the HARPSpol spectropolarimeter to observe the early B-type stars beta CMa (HD44743; B1 II/III) and epsilon CMa (HD52089; B1.5 II). For both stars, we…

HD 54879 is the most recently discovered magnetic O-type star. Previous studies ruled out a rotation period shorter than 7 years, implying that HD 54879 is the second most slowly-rotating known magnetic O-type star. We report new…

Solar and Stellar Astrophysics · Physics 2024-10-15 C. Erba , C. P. Folsom , A. David-Uraz , G. A. Wade , S. Seadrow , S. Bellotti , L. Fossati , V. Petit , M. E. Shultz

In our search for new magnetic massive stars we use the strongest indirect indicator of a magnetic field in B stars, which is periodic variability of UV stellar wind lines occurring in a velocity range symmetric around zero. Our aim is to…