Stellar Differential Rotation and Coronal Timescales
arXiv:1407.3388 · doi:10.1093/mnras/stu1415
Abstract
We investigate the timescales of evolution of stellar coronae in response to surface differential rotation and diffusion. To quantify this we study both the formation time and lifetime of a magnetic flux rope in a decaying bipolar active region. We apply a magnetic flux transport model to prescribe the evolution of the stellar photospheric field, and use this to drive the evolution of the coronal magnetic field via a magnetofrictional technique. Increasing the differential rotation (i.e. decreasing the equator-pole lap time) decreases the flux rope formation time. We find that the formation time is dependent upon the geometric mean of the lap time and the surface diffusion timescale. In contrast, the lifetime of flux ropes are proportional to the lap time. With this, flux ropes on stars with a differential rotation of more than eight times the solar value have a lifetime of less than two days. As a consequence, we propose that features such as solar-like quiescent prominences may not be easily observable on such stars, as the lifetimes of the flux ropes which host the cool plasma are very short. We conclude that such high differential rotation stars may have very dynamical coronae.
References in corpus (19)
- Physics of Solar Prominences: II - Magnetic Structure and Dynamics
- Large-scale magnetic topologies of mid-M dwarfs
- The Dependence of Differential Rotation on Temperature and Rotation
- The Sun's Global Photospheric and Coronal Magnetic Fields: Observations and Models
- Magnetic fields and accretion flows on the classical T Tauri star V2129 Oph
- Magnetic cycles of the planet-hosting star tauBootis
- Magnetic cycles of the planet-hosting star Tau Bootis: II. a second magnetic polarity reversal
- Implications of mass and energy loss due to coronal mass ejections on magnetically-active stars
- The global magnetic topology of AB Doradus
- Solar Flares and Coronal Mass Ejections: A Statistically Determined Flare Flux-CME Mass Correlation
- Modelling the Global Solar Corona II: Coronal Evolution and Filament Chirality Comparison
- Helicity Condensation as the Origin of Coronal and Solar Wind Structure
- Modeling the Dispersal of an Active Region: Quantifying Energy Input into the Corona
- Differential rotation and meridional flow on the lower zero age main sequence: Reynolds stress versus baroclinic flow
- Chirality of High Latitude Filaments over Solar Cycle 23
- Magnetic fields and differential rotation on the pre-main sequence II: The early-G star HD 141943 - coronal magnetic field, H-alpha emission and differential rotation
- Magnetic fields and differential rotation on the pre-main sequence III: The early-G star HD 106506
- The Coronal Structure of AB Doradus
- Modelling surface magnetic field evolution on AB Doradus due to diffusion and surface differential rotation