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Related papers: A Model for (Quasi-)Periodic Multi-wavelength Phot…

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We report on the first global three-dimensional (3D) MHD simulations of disk accretion onto a rotating magnetized star through the Rayleigh-Taylor instability. The star has a dipole field misaligned relative to the rotation axis by a small…

Astrophysics · Physics 2018-01-17 Marina M. Romanova , Akshay K. Kulkarni , Richard V. E. Lovelace

The appearance and time variability of accreting millisecond X-ray pulsars (hereafter AMXPs, e.g. Wijnands & van der Klis 1998) depends strongly on the accretion rate, the effective viscosity and the effective magnetic diffusivity of the…

Astrophysics · Physics 2009-11-13 Marina M. Romanova , Akshay K. Kulkarni , Min Long , Richard V. E. Lovelace

The Sun and stars with low magnetic activity levels, become photometrically brighter when their activity increases. Magnetically more active stars display the opposite behaviour and get fainter when their activity increases. We reproduce…

Solar and Stellar Astrophysics · Physics 2015-06-19 A. I. Shapiro , S. K. Solanki , N. A. Krivova , W. K. Schmutz , W. T. Ball , R. Knaack , E. V. Rozanov , Y. C. Unruh

Dipper stars are a classification of young stellar objects that exhibit dimming variability in their light curves, dropping in brightness by 10-50%, likely induced by occultations due to circumstellar disk material. This variability can be…

We present 2D Monte Carlo radiative transfer simulations of prestellar cores. We consider two types of asymmetry: disk-like asymmetry, in which the core is denser towards the equatorial plane than towards the poles; and axial asymmetry, in…

Astrophysics · Physics 2009-11-10 D. Stamatellos , A. P. Whitworth , P. Andre , D. Ward-Thompson

We investigate the origin of photometric variability in the classical T Tauri star TW Hya by comparing light curves obtained by TESS and ground-based telescopes with light curves created using three-dimensional (3D) magnetohydrodynamic…

Solar and Stellar Astrophysics · Physics 2025-01-24 M. M. Romanova , C. C. Espaillat , J. Wendeborn , J. -F. Donati , P. P. Petrov , R. V. E. Lovelace

We investigate the young stellar objects (YSOs) in the Lynds~1641 (L1641) cloud using multi-wavelength data including Spitzer, WISE, 2MASS, and XMM covering ~1390 YSOs across a range of evolutionary stages. In addition, we targeted a…

Solar and Stellar Astrophysics · Physics 2015-06-15 Min Fang , Jinyoung Serena Kim , Roy van Boekel , Aurora Sicilia-Aguilar , Thomas Henning , Kevin Flaherty

Starspots are ubiquitous in young, low-mass stars, yet their impact on the spectral classification and fundamental parameter inference of pre-main sequence stars (PMS) has been largely overlooked. In this study, we demonstrate that cool…

Solar and Stellar Astrophysics · Physics 2025-07-30 Facundo Pérez Paolino , Jeff Bary , Benjamin Horner , Lynne A. Hillenbrand , Adolfo Carvalho

A fraction of the extreme horizontal branch stars of globular clusters exhibit a periodic light variability that has been attributed to rotational modulation caused by surface spots. These spots are believed to be connected to inhomogeneous…

Solar and Stellar Astrophysics · Physics 2024-01-22 J. Krticka , I. Krtickova , C. Moni Bidin , M. Kajan , S. Zaggia , L. Monaco , J. Janik , Z. Mikulasek , E. Paunzen

The discovery of high-amplitude brightness oscillations during type I X-ray bursts from six low-mass X-ray binaries has provided a powerful new tool to study the properties of matter at supranuclear densities, the effects of strong gravity,…

Astrophysics · Physics 2009-10-31 Nevin Weinberg , M. Coleman Miller , Donald Q. Lamb

Utilizing a decade-long unTimely dataset, supplemented by multi-band data from archives, we search for young stellar objects (YSOs) with variations larger than one magnitude in W1 band within a region of 110 square degrees in the Galactic…

Solar and Stellar Astrophysics · Physics 2024-06-27 Jiaxun Li , Tinggui Wang

Radiative transfer calculations of massive star formation are presented. These are based on the Turbulent Core Model of McKee & Tan and self-consistently included a hydrostatic core, an inside-out expansion wave, a zone of free-falling…

Solar and Stellar Astrophysics · Physics 2015-05-27 Yichen Zhang , Jonathan C. Tan

This summary talk aims at highlighting some of the remaining open issues regarding the physics of the magnetospheric accretion/ejection process in young stellar objects (YSOs). It lists a number of questions related to YSOs magnetic fields…

Solar and Stellar Astrophysics · Physics 2015-06-17 J. Bouvier

Episodic accretion is one of the competing models to explain the observed luminosity spread in young stellar clusters. These short-lived high accretion events could also have a strong impact on planet formation. Observations of…

Solar and Stellar Astrophysics · Physics 2024-01-29 Carlos Contreras Peña , Philip W. Lucas , Zhen Guo , Leigh Smith

(abridged) Accretion from disks onto young stars is thought to follow magnetic field lines from the inner disk edge to the stellar surface. The accretion flow thus depends on the geometry of the magnetic field. This paper extends previous…

Solar and Stellar Astrophysics · Physics 2015-05-30 Fred C. Adams , Scott G. Gregory

Planet migration within inner protoplanetary disks significantly influences exoplanet architectures. We investigate various migration mechanisms for young planets close to young stars. To quantify the stochastic migration driven by…

Earth and Planetary Astrophysics · Physics 2025-05-07 Arturo Cevallos Soto , Zhaohuan Zhu

Using the United Kingdom Infrared Telescope on Mauna Kea, we have carried out a new near-infrared J, H, K monitoring survey of almost a square degree of the star-forming Orion Nebula Cluster with observations on 120 nights over three…

Solar and Stellar Astrophysics · Physics 2015-10-14 Thomas S. Rice , Bo Reipurth , Scott J. Wolk , Luiz Paulo Vaz , N. J. G. Cross

Since the '80s the \textit{Einstein} observatory has shown the Young Stellar Objects (YSOs), emit X-rays with luminosities, in the 0.3--8 keV bandpass, up to $\rm 10^3$--$\rm 10^4$ times than the Sun and that the X-ray emission is highly…

Solar and Stellar Astrophysics · Physics 2023-04-05 Salvatore Sciortino

Magnetospheric accretion is a key process that shapes the inner disks of T Tauri stars, controlling mass and angular momentum evolution. It produces strong ultraviolet and optical emission that irradiates the planet-forming environment. In…

The near-star environment around young stars is very dynamic with winds, disks, and outflows. These processes are involved in star and planet formation, and influence the formation and habitability of planets around host stars. Even for the…

Astrophysics · Physics 2007-11-19 D. M. Harrington , J. R. Kuhn