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We critically examine the constraints on internal angular momentum transport which can be inferred from the spin down of open cluster stars. The rotation distribution inferred from rotation velocities and periods are consistent for larger…

Solar and Stellar Astrophysics · Physics 2014-11-20 Pavel A. Denissenkov , Marc Pinsonneault , Donald M. Terndrup , Grant Newsham

Open star clusters from the MWSC (Milky Way Star Clusters) catalogue have been used to determine the Galactic rotation parameters. The circular rotation velocity of the solar neighborhood around the Galactic center has been found from data…

Astrophysics of Galaxies · Physics 2016-09-30 V. V. Bobylev , A. T. Bajkova , K. S. Shirokova

The intense turbulence present in the solar convection zone is a major challenge to both theory and simulation as one tries to understand the origins of the striking differential rotation profile with radius and latitude that has been…

Astrophysics · Physics 2009-11-07 Allan Sacha Brun , Juri Toomre

It is proposed that the observed near-surface inflows towards the active regions and sunspot zones provide a nonlinear feedback mechanism that limits the amplitude of a Babcock-Leighton-type solar dynamo and determines the variation of the…

Solar and Stellar Astrophysics · Physics 2015-06-11 R. H. Cameron , M. Schuessler

We present results of two simulations of the convection zone, obtained by solving the full hydrodynamic equations in a section of a spherical shell. The first simulation has cylindrical rotation contours (parallel to the rotation axis) and…

Astrophysics · Physics 2009-10-31 Francis J. Robinson , Kwing L. Chan

Stellar variability due to magnetic activity and flows at different spatial scales strongly impacts radial velocities. This variability is seen as oscillations, granulation, supergranulation, and meridional flows. The effect of this latter…

Solar and Stellar Astrophysics · Physics 2020-06-17 Nadège Meunier , Anne-Marie Lagrange

Context: The internal rotation of the Sun constitutes a fundamental constraint when modelling angular momentum transport in stellar interiors. In addition to the more external regions of the solar radiative zone probed by pressure modes,…

Solar and Stellar Astrophysics · Physics 2019-11-20 P. Eggenberger , G. Buldgen , S. J. A. J Salmon

We simulate the effect of latitudinal variations in the location of star spots, as well as their magnetic field strength, on stellar angular momentum loss to the stellar wind. We use the Michigan solar corona global MagnetoHydroDynamic…

Solar and Stellar Astrophysics · Physics 2009-07-22 O. Cohen , J. J. Drake , V. L. Kashyap , T. I. Gombosi

The aim of this work is to investigate rotation profile of solar-like stars with magnetic fields. A diffusion coefficient of magnetic angular momentum transport is deduced. Rotating stellar models with different mass are computed under the…

Astrophysics · Physics 2008-12-23 Wuming Yang , Shaolan Bi

We use global and local helioseismic inversions to explore the prevailing dynamical balances in the solar Near-Surface Shear Layer (NSSL). The differential rotation and meridional circulation are intimately linked, with a common origin in…

Solar and Stellar Astrophysics · Physics 2015-05-28 Mark S. Miesch , Bradley W. Hindman

It is known that the tilt angles of active regions increase with their latitude (Joy's law). It has never been checked before, however, whether the average tilt angles change from one cycle to another. Flux transport models show the…

Solar and Stellar Astrophysics · Physics 2015-05-18 Maria Dasi-Espuig , Sami K. Solanki , Natasha A. Krivova , Robert H. Cameron , Tania Peñuela

Observations of the meridional circulation of the Sun, which plays a key role in the operation of the solar dynamo, indicate that its speed varies with the solar cycle, becoming faster during the solar minima and slower during the solar…

Solar and Stellar Astrophysics · Physics 2017-10-11 Gopal Hazra , Arnab Rai Choudhuri

The average tilt angle of sunspot groups emerging throughout the solar cycle determines the net magnetic flux crossing the equator, which is correlated with the strength of the subsequent cycle. I suggest that a deep-seated, non-local…

Solar and Stellar Astrophysics · Physics 2015-10-28 Emre Işık

The effect of solar rotation on the proton-alpha differential flow speed, $v_{\alpha p}$, and consequently on the angular momentum transport in the solar wind, is explored. It is found that the force introduced by the azimuthal components…

Astrophysics · Physics 2011-02-11 Bo Li , Shadia Rifai Habbal , Xing Li

The rotational profile of the Sun is considered to be one of the key inputs in a solar dynamo model. Hence, precise and long-term measurements of this quantity is important for our understanding of solar magnetism and its variability. In…

Solar and Stellar Astrophysics · Physics 2021-02-02 Bibhuti Kumar Jha , Aditya Priyadarshi , Sudip Mandal , Subhamoy Chaterjee , Dipankar Banerjee

Measuring the depth variation of the meridional flows is important for understanding the solar cycle, at least according to a number of dynamo models. While attempting to extend the early observations of \citet{giles_thesis} of…

Solar and Stellar Astrophysics · Physics 2012-08-27 Thomas L. Duvall, , Shravan M. Hanasoge

A theory of the mean tilt of sunspot bipolar regions (the angle between a line connecting the leading and following sunspots and the solar equator) is developed. A mechanism of formation of the mean tilt is related to the effect of Coriolis…

Solar and Stellar Astrophysics · Physics 2020-08-04 N. Kleeorin , N. Safiullin , K. Kuzanyan , I. Rogachevskii , A. Tlatov , S. Porshnev

I investigate the suggestion that the Hyades moving group in the Solar neighbourhood is the result of a recent inner Lindblad resonance. I use dynamical "torus" models of the Galaxy to understand the expected distribution of solar…

Astrophysics of Galaxies · Physics 2015-05-28 Paul J. McMillan

Differential rotation is a key driver of magnetic activity and dynamo processes in the Sun and other stars, especially as the rate differs across the solar layers, but also in active regions. We aim to accurately quantify the velocity at…

Where and under what conditions the transfer of energy between electromagnetic fields and particles takes place in the solar wind remains an open question. We investigate the conditions that promote the growth of kinetic instabilities…