Giant coronal loops dominate the quiescent X-ray emission in rapidly rotating M stars

Abstract

Observations indicate that magnetic fields in rapidly rotating stars are very strong, on both small and large scales. What is the nature of the resulting corona? Here we seek to shed some light on this question. We use the results of an anelastic dynamo simulation of a rapidly rotating fully-convective M-star to drive a physics-based model for the stellar corona. We find that due to the several kilo Gauss large-scale magnetic fields at high latitudes, the corona and its X-ray emission are dominated by star-size large hot loops, while the smaller, underlying colder loops are not visible much in the X-ray. Based on this result we propose that, in rapidly rotating stars, emission from such coronal structures dominates the quiescent, cooler but saturated X-ray emission.

arXiv comment9 pages, 4 figures, accepted to ApJ

References in corpus (28)

• The stellar activity-rotation relationship and the evolution of stellar dynamos
• The Origin of T Tauri X-ray Emission: New Insights from the Chandra Orion Ultradeep Project
• Alfven Wave Solar Model (AWSoM): Coronal Heating
• Large-scale magnetic topologies of late M dwarfs
• Stellar magnetism: empirical trends with age and rotation
• Coronal Holes
• Improved angular momentum evolution model for solar-like stars
• The First Direct Measurements of Magnetic Fields on Very Low-Mass Stars
• Magnetic Braking Formulation for Sun-Like Stars: Dependence on Dipole Field Strength and Rotation Rate
• Driving major solar flares and eruptions: a review
• Solar-type dynamo behaviour in fully convective stars without a tachocline
• The Sun in Time: Activity and Environment
• The evolution of surface magnetic fields in young solar-type stars I: the first 250 Myr
• M-dwarf stellar winds: the effects of realistic magnetic geometry on rotational evolution and planets
• Effects of compressibility on driving zonal flow in gas giants
• Are Coronae of Magnetically Active Stars Heated by Flares? II. EUV and X-Ray Flare Statistics and the Differential Emission Measure Distribution
• Explaining the coexistence of large-scale and small-scale magnetic fields in fully convective stars
• On the magnetic topology of partially and fully convective stars
• Dipolar versus multipolar dynamos: the influence of the background density stratification
• Scaling laws of solar and stellar flares
• A study of X-ray flares - II. RS CVn type Binaries
• The Independency of Stellar Mass Loss Rates on stellar X-ray Luminosity and Activity Level based on Solar X-ray flux and Solar Wind Observations
• Formation of starspots in self-consistent global dynamo models: Polar spots on cool stars
• Consistent scaling laws in anelastic spherical shell dynamos
• Modelling the Hidden Magnetic Field of Low-Mass Stars
• Scaling Laws and Temperature Profiles for Solar and Stellar Coronal Loops with Non-uniform Heating
• A 33 year constancy of the X-ray coronae of AR Lac and eclipse diagnosis of scale height
• Scaling laws of coronal loops compared to a 3D MHD model of an Active Region

Cited by in corpus (7)

• Suppression of Coronal Mass Ejections in active stars by an overlying large-scale magnetic field: A numerical study
• High-resolution spectroscopy of flares and CMES on AD Leo*
• Coronal response to magnetically-suppressed CME events in M-dwarf stars
• Tuning the Exo-Space Weather Radio for Stellar Coronal Mass Ejections
• Evolution of X-ray Activity in <25 Myr Old Pre-Main Sequence Stars
• TESS observations of flares and quasi-periodic pulsations from low mass stars and potential impact on exoplanets
• X-ray Super-Flares From Pre-Main Sequence Stars: Flare Modeling