Evolution of solar-type stellar winds

Astrospheres and Solar-like Stellar Winds

Stellar analogs for the solar wind have proven to be frustratingly difficult to detect directly. However, these stellar winds can be studied indirectly by observing the interaction regions carved out by the collisions between these winds and the interstellar medium (ISM). These interaction regions are called "astrospheres", analogous to the "heliosphere" surrounding the Sun. The heliosphere and...

Tracing the Evolution and Impact of the Stellar Winds of Solar-Like Stars

Magnetic collimation of the solar and stellar winds

We resolve the paradox that although magnetic collimation of an isotropic solar wind results in an enhancement of its proton flux along the polar directions, several observations indicate a wind proton flux peaked at the equator. To that goal, we solve the full set of the timedependent MHD equations describing the axisymmetric outflow of plasma from the magnetized and rotating Sun, either in it...

Evolution of stellar winds from the Sun to red giants

By performing global 1D MHD simulations, we investigate the heating and acceleration of solar and stellar winds in open magnetic field regions. Our simulation covers from photosphere to 20-60 stellar radii, and takes into account radiative cooling and thermal conduction. We do not adopt ad hoc heating function; heating is automatically calculated from the solutions of Riemann problem at the cel...

Radio observations of stellar winds from early type stars

FifteenO andB supergiants have been observedwith the Very Large Array (VLA) at 4.85, 8.45, and 14.95 GHz in order to make a detailed comparative study of the mass loss rates evaluated from Hα and radio continuum observations and reveal and quantify possible departures from standardwind conditions. We detected 12 sources, 7 of which for the first time, thus increasing by 30% the total number of ...