Mass Loss of Solar-like Dwarf Stars and the Young Sun
Abstract
The collision of an ionized stellar wind with the partially-ionized warm gas in the interstellar medium creates a population of hot decelerated neutral hydrogen atoms. This ""hydrogen wall"" produces a blue-shifted absorption component in the stellar Lyman alpha emission line that has now been detected in HST spectra of 6 dwarf stars. Comparisons of the observed Lyman alpha line profiles with theoretical models lead to the first very sensitive measurements of mass loss rates as small as 4 x 10-15 solar masses per year for solar-like dwarf stars. Our program provides the first observational data (other than for the Sun) with which to test theories for the winds of solar-like dwarf stars. We find an empirical correlation of stellar mass loss rate with X-ray surface flux that allows us to predict the mass loss rates of other stars and to infer the solar wind flux at earlier times when the solar wind may have been as much as 1000 times more massive. We mention some important ramifications for the history of planetary atmospheres in our solar system that of Mars in particular and for exoplanets around stars.
- Publication:
-
Stars as Suns : Activity, Evolution and Planets
- Pub Date:
- January 2004
- Bibcode:
- 2004IAUS..219..898L