Dynamo modelling for cycle variability and occurrence of grand minima in Sun-like stars: Rotation rate dependence

Abstract

Like the solar cycle, stellar activity cycles are also irregular. Observations reveal that rapidly rotating (young) Sun-like stars exhibit a high level of activity with no Maunder-like grand minima and rarely display smooth regular activity cycles. On the other hand, slowly rotating old stars like the Sun have low activity levels and smooth cycles with occasional grand minima. We, for the first time, try to model these observational trends using flux transport dynamo models. Following previous works, we build kinematic dynamo models of one solar mass star with different rotation rates. Differential rotation and meridional circulation are specified with a mean-field hydrodynamic model. We include stochastic fluctuations in the Babcock-Leighton source of the poloidal field to capture the inherent fluctuations in the stellar convection. Based on extensive simulations, we find that rapidly rotating stars produce highly irregular cycles with strong magnetic fields and rarely produce Maunder-like grand minima, whereas the slowly-rotating stars (with a rotation period of 10 days and longer) produce smooth cycles of weaker strength, long-term modulation in the amplitude, and occasional extended grand minima. The average duration and the frequency of grand minima increase with decreasing rotation rate. These results can be understood as the tendency of less supercritical dynamo in slower rotating stars to be more prone to produce extended grand minima

Accepted in MNRAS

References in corpus (26)

• Stellar magnetism: empirical trends with age and rotation
• Solar-type dynamo behaviour in fully convective stars without a tachocline
• The crucial role of surface magnetic fields for the solar dynamo
• Meridional Circulation in Solar and Stellar Convection Zones
• On differential rotation and overshooting in solar-like stars
• Effects of the scatter in sunspot group tilt angles on the large-scale magnetic field at the solar surface
• Rapidly Rotating Suns and Active Nests of Convection
• Magnetically controlled stellar differential rotation near the transition from solar to anti-solar profiles
• Solar Cycle Variability Induced by Tilt Angle Scatter in a Babcock--Leighton Solar Dynamo Model
• Powering Stellar Magnetism: Energy Transfers in Cyclic Dynamos of Sun-like Stars
• Understanding solar cycle variability
• Sunspot positions, areas, and group tilt angles for 1611-1631 from observations by Christoph Scheiner
• Five Decades of Chromospheric Activity in 59 Sun-like Stars and New Maunder Minimum Candidate HD 166620
• Nonlinear mechanisms that regulate the solar cycle amplitude
• Re-examining Sunspot Tilt Angle to Include Anti-Hale Statistics
• Polar Network Index as a magnetic proxy for the solar cycle studies
• Quenching and anisotropy of hydromagnetic turbulent transport
• The crucial role of surface magnetic fields for stellar dynamos: Epsilon Eridani, 61 Cygni A, and the Sun
• Waldmeier Effect in Stellar Cycles
• Is the Hemispheric Asymmetry of Monthly Sunspot Area an Irregular Process with Long-Term Memory?
• Nature of grand minima and maxima from fully non-linear Flux-Transport Dynamos
• Stellar Dynamos with Solar and Anti-solar Differential Rotations: Implications to Magnetic Cycles of Slowly Rotating Stars
• Toroidal flux loss due to flux emergence explains why solar cycles rise differently but decay in a similar way
• Dependence of magnetic cycle parameters on period of rotation in nonlinear solar-type dynamos
• Impact of anti-solar differential rotation in mean-field solar-type dynamos -- Exploring possible magnetic cycles in slowly rotating stars
• The Dependence of Stellar Activity Cycles on Effective Temperature

Cited by in corpus (9)

• Models for the long-term variations of solar activity
• Asteroseismology and Spectropolarimetry of the Exoplanet Host Star $\lambda$ Serpentis
• A BCool survey of stellar magnetic cycles
• Modeling effects of starspots on stellar magnetic cycles
• TESS asteroseismology of $\beta$ Hydri: a subgiant with a born-again dynamo
• Weakened Magnetic Braking Signals the Collapse of the Global Stellar Dynamo
• Role of sunspot latitude versus tilt in determining the polar field and amplitude of the next cycle: Cause of the weak Solar Cycle 20
• Stellar cycle variability in Mount Wilson stars and dynamo models: Rotation rate and dynamo number dependency
• Stellar Activity Cycles Grow Longer and Weaker Before Disappearing