New Mass-Loss Measurements from Astrospheric Lyα Absorption

Abstract

Measurements of stellar mass loss rates are used to assess how wind strength\nvaries with coronal activity and age for solar-like stars. Mass loss generally\nincreases with activity, but we find evidence that winds suddenly weaken at a\ncertain activity threshold. Very active stars are often observed to have polar\nstarspots, and we speculate that the magnetic field geometry associated with\nthese spots may be inhibiting the winds. Our inferred mass-loss/age relation\nrepresents an empirical estimate of the history of the solar wind. This result\nis important for planetary studies as well as solar/stellar astronomy, since\nsolar wind erosion may have played an important role in the evolution of\nplanetary atmospheres.\n