Solar-type dynamo behaviour in fully convective stars without a tachocline

Understand

In solar-type stars (with radiative cores and convective envelopes), the magnetic field powers star spots, flares and other solar phenomena, as well as chromospheric and coronal emission at ultraviolet to X-ray wavelengths.

• The dynamo responsible for generating the field depends on the shearing of internal magnetic fields by differential rotation.
• The shearing has long been thought to take place in a boundary layer known as the tachocline between the radiative core and the convective envelope.
• Fully convective stars do not have a tachocline and their dynamo mechanism is expected to be very different, although its exact form and physical dependencies are not known.