Recent observations of soft X-ray emission from solar-type stars obtained with the Einstein X-Ray Observatory indicate that X-ray luminosity is inversely correlated with stellar age. If this result is applied to the Sun and if X-ray emission is a valid indicator of other manifestations of solar activity, then past solar wind and flare levels can be inferred. It can qualitatively explain the excess xenon and nitrogen found in the lunar regolith compared to the level expected from the comteporary solar wind. X-Ray emission from T Tauri and other low-mass pre-main-sequence stars is both highly luminous and variable, indicating the presence of flares ∼4 × 103 times stronger than the largest flares seen in the contemporary Sun. The proton flux from such solar flares during the 106 to 107-year pre-main-sequence phase would be sufficient to account for the 26Al anomaly n meteorites.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science