Zobrazeno 1 - 10
of 97
pro vyhledávání: '"Petri J. Käpylä"'
Autor:
Petri J. Käpylä, Nishant K. Singh
Turbulent motions enhance the diffusion of large-scale flows and temperature gradients. Such diffusion is often parameterized by coefficients of turbulent viscosity ($\nu_{\rm t}$) and turbulent thermal diffusivity ($\chi_{\rm t}$) that are analogous
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0955185034eb5fd3d11351fce49bd682
Autor:
Felipe H. Navarrete, Dominik R. G. Schleicher, Petri J. Käpylä, Carolina A. Ortiz-Rodríguez, Robi Banerjee
Publikováno v:
Astronomy & Astrophysics. 667:A164
Eclipsing time variations (ETVs) in post-common-envelope binaries (PCEBs) were proposed to be due to the time-varying component of the stellar gravitational quadrupole moment. This is suggested to be produced by changes in the stellar structure due t
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3d517c76db1e3dc171cd9dc57180c96f
https://doi.org/10.1051/0004-6361/202243917
https://doi.org/10.1051/0004-6361/202243917
Autor:
Petri J. Käpylä
Publikováno v:
Astronomische Nachrichten. 340:744-751
The $\Lambda$ effect describes a rotation-induced non-diffusive contribution to the Reynolds stress. It is commonly held responsible for maintaining the observed differential rotation of the Sun and other late-type stars. Here the sensitivity of the
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::64fece1d2d282624d63dd4cb2dca20fc
https://doi.org/10.1002/asna.201913632
https://doi.org/10.1002/asna.201913632
Publikováno v:
GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS. 113(1-2):149-183
We consider the effect of a subadiabatic layer at the base of the convection zone on convection itself and the associated large-scale dynamos in spherical wedge geometry. We use a heat conduction prescription based on the Kramers opacity law which al
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::533e3d11550a598644910af544034cb2
http://juuli.fi/Record/0337983019
http://juuli.fi/Record/0337983019
Autor:
Felipe H. Navarrete, Petri J. Käpylä, Dominik R. G. Schleicher, Carolina A. Ortiz, Robi Banerjee
Publikováno v:
Astronomy & Astrophysics. 663:A90
The possibility to detect circumbinary planets and to study stellar magnetic fields through eclipsing time variations (ETVs) in binary stars has sparked an increase of interest in this area of research. We revisit the connection between stellar magne
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9eacf0228c675ad194029bb0ddcbccb7
https://doi.org/10.1051/0004-6361/202243252
https://doi.org/10.1051/0004-6361/202243252
The Navier-Stokes equations generate an infinite set of generalized Lyapunov exponents defined by different ways of measuring the distance between exponentially diverging perturbed and unperturbed solutions. This set is demonstrated to be similar, ye
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::13ab64b786614fee185d956a7c708e53
http://arxiv.org/abs/2104.01235
http://arxiv.org/abs/2104.01235
Autor:
Petri J. Käpylä
(abridged) Context: Main-sequence late-type stars with masses less than $0.35 M_\odot$ are fully convective. Aims: The goal is to study convection, differential rotation, and dynamos as functions of rotation in fully convective stars. Methods: Three-
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c5c5686ff3f7cf0126e8b2265eb4f74f
http://arxiv.org/abs/2012.01259
http://arxiv.org/abs/2012.01259
Autor:
Petri J. Käpylä
Publikováno v:
Astronomy & Astrophysics. 655:A78
Context. The ratio of kinematic viscosity to thermal diffusivity, the Prandtl number, is much smaller than unity in stellar convection zones. Aims. The main goal of this work is to study the statistics of convective flows and energy transport as func
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::8c18ac4325326e78520d4a9d4465378a
https://doi.org/10.1051/0004-6361/202141337
https://doi.org/10.1051/0004-6361/202141337
Publikováno v:
Astronomy & Astrophysics
Context.Results from helioseismology indicate that the radial gradient of the rotation rate in the near-surface shear layer (NSSL) of the Sun is independent of latitude and radius. Theoretical models using the mean-field approach have been successful
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d4b63317ea13d431f5adb9a8a523db3c
https://doi.org/10.1051/0004-6361/202040052
https://doi.org/10.1051/0004-6361/202040052
Rotating stellar convection transports angular momentum towards the equator, generating the characteristic equatorial acceleration of the solar rotation while the radial flux of angular momentum is always inwards. New numerical box simulations for th
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b282059b98aa352a3d298fb7f14f26f8
http://arxiv.org/abs/1902.04172
http://arxiv.org/abs/1902.04172