Effect of partial mixing of matter on the hydrodynamic angular momentum transport processes in massive main-sequence stars

2009 ◽  
Vol 35 (6) ◽  
pp. 413-423 ◽  
Author(s):  
E. I. Staritsin
Solar Physics ◽  
1990 ◽  
Vol 128 (1) ◽  
pp. 287-298 ◽  
Author(s):  
C. Vigneron ◽  
A. Mangeney ◽  
C. Catala ◽  
E. Schatzman

2015 ◽  
Vol 11 (A29B) ◽  
pp. 661-666
Author(s):  
Othman Benomar ◽  
Masao Takata ◽  
Hiromoto Shibahashi ◽  
Tugdual Ceillier ◽  
Rafael A. García

AbstractThe rotation rates in the interior and at the surface is determined for the 22 main-sequence stars with masses between 1.0 and 1.6 M⊙. The average interior rotation is measured using asteroseismology, while the surface rotation is measured by the spectroscopic v sin i or the periodic light variation due to surface structures, such as spots. It is found that the difference between the surface rotation rate determined by spectroscopy and the average rotation rate for most of stars is small enough to suggest that an efficient process of angular momentum transport operates during and/or before the main-sequence stage of stars. By comparing the surface rotation rate measured from the light variation with those measured by spectroscopy, we found hints of latitudinal differential rotation. However, this must be confirmed by a further study because our result is sensitive to a few data points.


2001 ◽  
Vol 200 ◽  
pp. 406-409 ◽  
Author(s):  
Caroline E. J. M. L. J. Terquem

We discuss the transport of angular momentum induced by tidal effects in a disk surrounding a star in a pre–main sequence binary system. We consider the effect of both density and bending waves. Although tidal effects are important for truncating protostellar disks and for determining their size, it is unlikely that tidally–induced angular momentum transport plays a dominant role in the evolution of protostellar disks. Where the disk is magnetized, transport of angular momentum is probably governed by MHD turbulence. In a non self–gravitating laminar disk, the amount of transport provided by tidal waves is probably too small to account for the lifetime of protostellar disks. In addition, tidal effects tend to be localized in the disk outer regions.


2013 ◽  
Vol 9 (S301) ◽  
pp. 377-378
Author(s):  
Lucie Alvan ◽  
Stéphane Mathis ◽  
Thibaut Decressin

AbstractGravity waves, which propagate in radiation zones, can extract or deposit angular momentum by radiative and viscous damping. Another process, poorly explored in stellar physics, concerns their direct interaction with the differential rotation and the related turbulence. In this work, we thus study their corotation resonances, also called critical layers, that occur where the Doppler-shifted frequency of the wave approaches zero. First, we study the adiabatic and non-adiabatic propagation of gravity waves near critical layers. Next, we derive the induced transport of angular momentum. Finally, we use the dynamical stellar evolution code STAREVOL to apply the results to the case of a solar-like star. The results depend on the value of the Richardson number at the critical layer. In the first stable case, the wave is damped. In the other unstable and turbulent case, the wave can be reflected and transmitted by the critical layer with a coefficient larger than one: the critical layer acts as a secondary source of excitation for gravity waves. These new results can have a strong impact on our understanding of angular momentum transport processes in stellar interiors along stellar evolution where strong gradients of angular velocity can develop.


2001 ◽  
Vol 200 ◽  
pp. 410-414
Author(s):  
Günther Rüdiger ◽  
Udo Ziegler

Properties have been demonstrated of the magneto-rotational instability for two different applications, i.e. for a global spherical model and a box simulation with Keplerian background shear flow. In both nonlinear cases a dynamo operates with a negative (positive) α-effect in the northern (southern) disk hemisphere and in both cases the angular momentum transport is outwards. Keplerian accretion disks should therefore exhibit large-scale magnetic fields with a dipolar geometry of the poloidal components favoring jet formation.


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