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Related papers: Unstable accretion in TW Hya: 3D simulations and c…

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Observations of jets from young stellar objects reveal the asymmetric outflows from some sources. A large set of $2.5$D MHD simulations has been carried out for axisymmetric viscous/diffusive disc accretion to rotating magnetized stars for…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Sergei Dyda , Richard V. E. Lovelace , Galina V. Ustyugova , Patrick S. Lii , Marina M. Romanova , Alexander V. Koldoba

The aim of this work is to characterize the accretion process of the classical T Tauri Star RU Lup. We studied optical high-resolution spectroscopic observations from CHIRON and ESPRESSO, obtained simultaneously with photometric data from…

The Dwarf Nova Oscillations observed in Cataclysmic Variable (CV) stars are interpreted in the context of a Low Inertia Accretor model, in which accretion on to an equatorial belt of the white dwarf primary causes the belt to vary its…

Astrophysics · Physics 2009-11-07 Brian Warner , Patrick A. Woudt

We present the results of an intensive coordinated monitoring campaign in the optical and X-ray wavelength ranges of the low-mass, pre-main sequence star V410Tau carried out with the aim to study the relation between various indicators for…

In this paper, the period evolution of the rotating chemically peculiar star V473\,Tau is investigated. Even though the star has been observed for more than fifty years, for the first time four consecutive years of space-based data covering…

Solar and Stellar Astrophysics · Physics 2018-07-27 Dogus Ozuyar , Ian R. Stevens

It is now accepted that accretion onto classical T Tauri stars is controlled by the stellar magnetosphere, yet to date most accretion models have assumed that their magnetic fields are dipolar. By considering a simple steady state accretion…

Astrophysics · Physics 2009-11-11 S. G. Gregory , M. Jardine , I. Simpson , J. -F. Donati

Previous studies have related surface temperature maps, obtained with the Doppler imaging (DI) technique, of LQ Hya with long-term photometry. We compare surface magnetic field maps, obtained with the Zeeman Doppler imaging (ZDI) technique,…

The space telescope CoRoT has provided light curves of T Tauri stars belonging to the star-forming region of NGC 2264 with unprecedented continuity and precision in the framework of a coordinated multi-wavelength observational project. We…

Solar and Stellar Astrophysics · Physics 2016-08-17 A. F. Lanza , E. Flaccomio , S. Messina , G. Micela , I. Pagano , G. Leto

We observed persistent high-frequency oscillations of the boundary layer near an accreting, weakly-magnetized star in global 3D MHD simulations. The tilted dipole magnetic field is not strong enough to open a gap between the star and the…

Solar and Stellar Astrophysics · Physics 2015-06-17 A. A. Blinova , M. Bachetti , M. M. Romanova

Global magnetohydrodynamic (MHD) instabilities are investigated in a computationally tractable two-dimensional model of the solar tachocline. The model's differential rotation yields stability in the absence of a magnetic field, but if a…

Plasma Physics · Physics 2019-02-19 Abigail Plummer , J. B. Marston , S. M. Tobias

Magnetic, chemically peculiar stars are known for exhibiting surface abundance inhomogeneities (chemical spots) that lead to photometric and spectroscopic variability with the rotation period. It is commonly assumed that the surface…

Solar and Stellar Astrophysics · Physics 2019-02-20 M. Jagelka , Z. Mikulášek , S. Hümmerich , E. Paunzen

CI Tau is a young (~2 Myr) classical T Tauri star located in the Taurus star forming region. Radial velocity observations indicate it hosts a Jupiter-sized planet with an orbital period of approximately 9 days. In this work, we analyze time…

Earth and Planetary Astrophysics · Physics 2018-02-21 Lauren I. Biddle , Christopher M. Johns-Krull , Joe Llama , Lisa Prato , Brian A. Skiff

AA Tau, a classical T Tauri star in the Taurus cloud, has been the subject of intensive photometric monitoring for more than two decades due to its quasi-cyclic variation in optical brightness. Beginning in 2011, AA Tau showed another…

Solar and Stellar Astrophysics · Physics 2015-05-27 Ke Zhang , Nathan Crockett , Colette Salyk , Klaus Pontoppidan , Neal J. Turner , John M. Carpenter , Geoffrey A. Blake

We discuss three modes of oscillation of accretion disks around rotating magnetized neutron stars which may explain the separations of the kilo-Hertz quasi periodic oscillations (QPO) seen in low mass X-ray binaries. The existence of these…

High Energy Astrophysical Phenomena · Physics 2009-07-24 R. V. E. Lovelace , L. Turner , M. M. Romanova

We present Very Large Array observations at 3.5 cm of the nearby young star TW Hya that show the emission is constant in time over weeks, months and years, and spatially resolved with peak brightness temperature ~10 K at ~0.25 (15 AU)…

Astrophysics · Physics 2009-11-13 D. J. Wilner , P. D'Alessio , N. Calvet , M. J. Claussen , L. Hartmann

Serious theoretical effort has been devoted to explain the observed frequencies of twin-peak quasi-periodic oscillations (HF QPOs) observed in low-mass X-ray neutron star binaries. Here we propose a new model of HF QPOs. Within its…

High Energy Astrophysical Phenomena · Physics 2016-03-15 Gabriel Török , Kateřina Goluchová , Jiří Horák , Eva Šrámková , Martin Urbanec , Tomáš Pecháček , Pavel Bakala

In this article we show that the, mainly spacetime, w-modes may become unstable in a rotating ultracompact ($R<3M$) relativistic star. We provide results for the axial modes of a rotating star in the slow rotation approximation, and…

Astrophysics · Physics 2009-11-07 K. D. Kokkotas , J. Ruoff , N. Andersson

This paper exploits spectropolarimetric data of the classical T Tauri star CI Tau collected with ESPaDOnS at the Canada-France-Hawaii Telescope, with the aims of detecting and characterizing the large-scale magnetic field that the star…

Solar and Stellar Astrophysics · Physics 2020-01-08 JF Donati , J Bouvier , SH Alencar , C Moutou , L Malo , M Takami , F Menard , C Dougados , GA Hussain , the MaTYSSE collaboration