Related papers: Single-hemisphere dynamos in M-dwarf stars
Stable, hydrogen-burning, M dwarf stars comprise about 75% of all stars in the Galaxy. They are extremely long-lived and because they are much smaller in mass than the Sun (between 0.5 and 0.08 MSun), their temperature and stellar…
Several solar-like stars exhibit cyclic magnetic activity similar to the Sun as found in photospheric and chromospheric emission. We want to understand the physical mechanism involved in rotational dependence of these activity cycle…
We live near a magnetic star whose cycles of activity are driven by dynamo action beneath the surface. In the solar convection zone, rotation couples with plasma motions to build highly organized magnetic fields that erupt at the surface…
We have examined the relationship between rotation and activity in 14 late-type (M6-M7) M dwarfs, using high resolution spectra taken at the W.M. Keck Observatory and flux-calibrated spectra from the Sloan Digital Sky Survey. Most were…
Stellar dynamos are driven by complex couplings between rotation and turbulent convection, which drive global-scale flows and build and rebuild stellar magnetic fields. When stars like our sun are young, they rotate much more rapidly than…
Rotation is a directly-observable stellar property, and drives magnetic field generation and activity through a magnetic dynamo. Main sequence stars with masses below approximately 0.35Msun (mid-to-late M dwarfs) are fully-convective, and…
In recent years, observers have found that the fraction of M-stars demonstrating significant magnetic activity transitions sharply from roughly $10\%$ for main-sequence stars earlier (more massive) than spectral type M3.5 (0.35 M$_\odot$)…
We perform three-dimensional numerical simulations of stellar winds of early-M dwarf stars. Our simulations incorporate observationally reconstructed large-scale surface magnetic maps, suggesting that the complexity of the magnetic field…
The geo and solar magnetic fields have long been thought to be very different objects both in terms of spatial structure and temporal behavior. The recently discovered field structure of a fully convective star is more reminiscent of…
Early-type stars have convective cores due to a steep temperature gradient produced by the CNO cycle. These cores can host dynamos, and the generated magnetic fields can be relevant to explain the magnetism observed in Ap/Bp stars. Our main…
A new version of a numerical model of stellar differential rotation based on mean-field hydrodynamics is presented and tested by computing the differential rotation of the Sun. The model is then applied to four individual stars including…
Understanding how cool stars produce magnetic fields within their interiors is crucial for predicting the impact of such fields, such as the activity cycle of the Sun. In this respect, studying fully convective stars enables us to…
The evolution of angular momentum is a key to our understanding of star formation and stellar evolution. The rotational evolution of solar-mass stars is mostly controlled by magnetic interaction with the circumstellar disc and angular…
Close M-dwarf binaries and higher multiples allow the investigation of rotational evolution and mean magnetic flux unbiased from scatter in inclination angle and age since the orientation of the spin axis of the components is most likely…
Despite the lack of a shear-rich tachocline region low-mass fully convective stars are capable of generating strong magnetic fields, indicating that a dynamo mechanism fundamentally different from the solar dynamo is at work in these…
Main-sequence massive stars possess convective cores that likely harbor strong dynamo action. To assess the role of core convection in building magnetic fields within these stars, we employ the 3-D anelastic spherical harmonic (ASH) code to…
Recent results showed that the magnetic field of M-dwarf (dM) stars, currently the main targets in searches for terrestrial planets, is very different from the solar one, both in topology as well as in intensity. In particular, the…
The convective envelopes of cool main-sequence stars harbour magnetic fields with a complex global and local structure. These fields affect the near-surface convection and the outer stellar atmospheres in many ways and are responsible for…
Stellar rotation periods are valuable both for constraining models of angular momentum loss and for under- standing how magnetic features impact inferences of exoplanet parameters. Building on our previous work in the northern hemisphere,…
M dwarfs are prime targets in the hunt for habitable worlds around other stars. This is due to their abundance as well as their small radii and low masses and temperatures, which facilitate the detection of temperate, rocky planets in orbit…