Atmospheric Escape From Earth and Mars: Response to Solar and Solar Wind Drivers of Oxygen Escape

Habitability at the surface of a planet depends on having an atmosphere long enough for life to develop. The loss of atmosphere to space is an important component in assessing planetary surface habitability. Current models of atmospheric escape from exoplanets are not well constrained by observations. Atmospheric escape observations from the terrestrial planets are available in public data archives. We recast oxygen escape rates from Earth derived from an instrument on Dynamics Explorer‐1 as function of solar wind and compare them to similar data from Mars. Analysis demonstrates that oxygen escape rates from Mars are not as sensitive to variations in solar power components as those from Earth. Available data from Venus can confirm or refute the assertion that oxygen escape from magnetized planets is more sensitive than that from unmagnetized planets. Plain Language Summary Habitability of a planet depends on having an atmosphere long enough for life to develop. NASA and ESA data archives contain information about atmospheric escape from the terrestrial planets. For these planets oxygen ions dominate atmospheric escape. The data archives are just beginning to be analyzed and presented in a form that allows comparison with, and validation of, models of the interaction of stellar winds with exoplanets. We derive oxygen escape rates from Earth as a function of solar power components from a recasting of Dynamics Explorer‐1 data and compare them to similar data from Mars. Our analysis demonstrates that oxygen escape rates from Mars are not as sensitive to variations in the solar power components as those from Earth. These data and similar data from Venus will prove to be important constrains on models of stelar wind/atmosphere interactions and atmospheric escape from exoplanets. Key Points We recast oxygen escape rates from Earth derived from an instrument on Dynamics Explorer‐1 as a function of solar energy inputs We compare escape rates for a magnetized planet (Earth) and an unmagnetized planet (Mars) as a function of solar energy inputs Oxygen escape rates from Mars are not as sensitive to variations in the solar power components as those from Earth