Stellar Dynamos with Solar and Anti-solar Differential Rotations: Implications to Magnetic Cycles of Slowly Rotating Stars

Abstract

Simulations of magnetohydrodynamics convection in slowly rotating stars predict anti-solar differential rotation (DR) in which the equator rotates slower than poles. This anti-solar DR in the usual $\alpha \Omega$ dynamo model does not produce polarity reversal. Thus, the features of large-scale magnetic fields in slowly rotating stars are expected to be different than stars having solar-like DR. In this study, we perform mean-field kinematic dynamo modelling of different stars at different rotation periods. We consider anti-solar DR for the stars having rotation period larger than 30~days and solar-like DR otherwise. We show that with particular $\alpha$ profiles, the dynamo model produces magnetic cycles with polarity reversals even with the anti-solar DR provided, the DR is quenched when the toroidal field grows considerably high and there is a sufficiently strong $\alpha$ for the generation of toroidal field. Due to the anti-solar DR, the model produces an abrupt increase of magnetic field exactly when the DR profile is changed from solar-like to anti-solar. This enhancement of magnetic field is in good agreement with the stellar observational data as well as some global convection simulations. In the solar-like DR branch, with the decreasing rotation period, we find the magnetic field strength increases while the cycle period shortens. Both of these trends are in general agreement with observations. Our study provides additional support for the possible existence of anti-solar DR in slowly rotating stars and the presence of unusually enhanced magnetic fields and possibly cycles which are prone to production of superflare.

arXiv commentAccepted for publication in MNRAS

References in corpus (57)

• The stellar activity-rotation relationship and the evolution of stellar dynamos
• Toroidal versus poloidal magnetic fields in Sun-like stars: a rotation threshold
• The Dependence of Differential Rotation on Temperature and Rotation
• Chromospheric activity catalogue of 4454 cool stars. Questioning the active branch of stellar activity cycles
• Sunspot group tilt angles and the strength of the solar cycle
• Magnetic Cycles and Rotation Periods of Late Type Stars from photometric time series
• Full--Sphere Simulations of a Circulation--Dominated Solar Dynamo: Exploring the Parity Issue
• Generalized investigation of the rotation-activity relation: Favouring rotation period instead of Rossby number
• Solar-type dynamo behaviour in fully convective stars without a tachocline
• From solar-like to anti-solar differential rotation in cool stars
• The crucial role of surface magnetic fields for the solar dynamo
• Rotation, differential rotation, and gyrochronology of active Kepler stars
• Solar Cycle Propagation, Memory, and Prediction: Insights from a Century of Magnetic Proxies
• Meridional Circulation in Solar and Stellar Convection Zones
• A simulation of convective dynamo in the solar convective envelope: maintenance of the solar-like differential rotation and emerging flux
• Rapidly Rotating Suns and Active Nests of Convection
• Differential rotation in solar-like stars from global simulations
• Importance of Meridional Circulation in Flux Transport Dynamo: The Possibility of a Maunder-like Grand Minimum
• Magnetically controlled stellar differential rotation near the transition from solar to anti-solar profiles
• Differential rotation of main-sequence dwarfs and its dynamo-efficiency
• Multiple dynamo modes as a mechanism for long-term solar activity variations
• Confirmation of bistable stellar differential rotation profiles
• Exploring the $P_{cyc}$ vs $P_{rot}$ relation with flux transport dynamo models of solar-like stars
• Activity trends in young solar-type stars
• Solar rotation rate and its gradients during cycle 23
• Solar parity issue with flux-transport dynamo
• Does the Babcock--Leighton Mechanism Operate on the Sun?
• Simulations of turbulent convection in rotating young solar-like stars: Differential rotation and meridional circulation
• Transition from axi- to nonaxisymmetric dynamo modes in spherical convection models of solar-like stars
• The Waldmeier effect and the flux transport solar dynamo
• A Survey of Chromospheric Activity in the Solar-Type Stars in the Open Cluster M67
• Babcock-Leighton solar dynamo: the role of downward pumping and the equatorward propagation of activity
• Turbulent dynamos with shear and fractional helicity
• Turbulent transport coefficients in spherical wedge dynamo simulations of solar-like stars
• Double-peaks of the solar cycle: An explanation from a dynamo model
• Dynamo cycles in global convection simulations of solar-like stars
• Polar Network Index as a magnetic proxy for the solar cycle studies
• Oscillatory migrating magnetic fields in helical turbulence in spherical domains
• Oscillatory mean-field dynamos with spherically symmetric, isotropic alpha
• What sets the magnetic field strength and cycle period in solar-type stars?
• Characterisation of the turbulent electromotive force and its magnetically-mediated quenching in a global EULAG-MHD simulation of solar convection
• A dynamo model of magnetic activity in solar-like stars with different rotational velocities
• Quenching and anisotropy of hydromagnetic turbulent transport
• Consequences of high effective Prandtl number on solar differential rotation and convective velocity
• A method to discriminate solar and antisolar differential rotation in high-precision light curves
• How does the shape and thickness of the tachocline affect the distribution of the toroidal magnetic fields in the solar dynamo?
• Enhanced stellar activity for slow antisolar differential rotation?
• Stellar dynamos in the transition regime: multiple dynamo modes and anti-solar differential rotation
• Anti-solar differential rotation on the active sub-giant HU Virginis
• Waldmeier Effect in Stellar Cycles
• Exploring cycle period and parity of stellar magnetic activity with dynamo modeling
• Can superflares occur on the Sun? A view from dynamo theory
• Dynamo Saturation in Rapidly Rotating Solar-Type Stars
• Antisolar differential rotation with surface lithium enrichment on the single K-giant V1192 Orionis
• Solar-cycle variation of the rotational shear near the solar surface
• On the compatibility of a flux transport dynamo with a fast tachocline scenario
• Sharp magnetic structures from dynamos with density stratification

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• Stellar mid-life crisis: subcritical magnetic dynamos of solar-like stars and the breakdown of gyrochronology
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• Dynamo modelling for cycle variability and occurrence of grand minima in Sun-like stars: Rotation rate dependence
• Wavelet analysis of the long-term activity of V833 Tau
• The Hot Neptune WASP-166~b with ESPRESSO I: Refining the Planetary Architecture and Stellar Variability
• WASP-131 b with ESPRESSO I: A bloated sub-Saturn on a polar orbit around a differentially rotating solar-type star
• Hunting for anti-solar differentially rotating stars using the Rossby number -- An application to the Kepler field
• Impact of anti-solar differential rotation in mean-field solar-type dynamos -- Exploring possible magnetic cycles in slowly rotating stars
• New cases of super-flares on slowly rotating solar-type stars and large amplitude super-flares in G- and M-type main-sequence stars
• Magnetic field evolution in solar-type stars