Two dimensional mapping of the sodium emission in Europa's exosphere

Abstract

We present results of the mapping of Europa's sodium exosphere in two dimensions and through a period of time. We base this research on several observations taken in 2001 and 2002 with the McMath-Pierce Solar Telescope at Kitt Peak, Arizona. We have created sodium emission intensity maps and line of sight column abundance maps of Europa's exosphere in all directions. We include calculations of vertical and tangential column abundances as well as surface densities of sodium relative to the position of Europa and to the Io plasma torus. We find that the sodium exosphere is weakly bound or escaping along the East-West direction, but not to be escaping along the North-South direction. Additionally, we find that the sodium exosphere is energetic enough to extend to a distance of roughly 40,000 km away from the surface of Europa.