Close encounter with comet 46P/Wirtanen: X-ray tomography of the coma

In the 1990's it was discovered the comets emit X-rays. Our group lead the modeling of the first higher resolution X-ray spectra and we are continuing these studies using observations with Chandra/ACIS and HST/WFC3 to characterize the neutral gas and plasma around comet 46P/Wirtanen. We will use the comet s historic close approach to Earth as a natural laboratory to study charge exchange emission processes. First, we will combine x-ray and visible imaging to map the distribution and variability of gas in the coma. Second, the comet's close proximity allows us to investigate the emission mechanism responsible for faint >1 keV features previously seen in other comets. Third, we will compare the interactions of the solar wind with the gas molecules surrounding the comet and with local interstellar neutral atoms sweeping through the heliosphere. We will analyze the X-ray spectra with the standard Chandra modeling software and application of our charge exchange models for cometary X-ray emission.