The Heliosphere is a protective bubble that is formed by the plasma that makes up the solar wind interacting with interstellar plasma. This bubble acts as a sort of “Shield” that protects the earth from the harsh intergalatic environment. An astrosphere is the extrasolar equivalent to the Heliosphere.pia22835a_20181206_voyager_in_interstellar_space_annotated_1920x1080_72dpi-final An Astrosphere is predicted to play a similar protective role in other star systems and would have a direct impact on the habitability of exoplanets. If an Astrosphere is not strong enough to ward off particles, then a planet being in the traditional “habitable zone” may not be habitable after all.



The detection of Astrospheres is alone a daunting task. There are a few spectacular examples of strong astrospheres that are readily observable like the imageĀ  at the top of this page.


I am interested in observing astrospheres that are not as apparent. Lyman alpha absorption can be a key tool to observe astrospheres in these more subtle systems. Neutral hydrogen along the line of sight towards a given star along with Neutral hydrogen created in heliosphere absorb specific wavelengths that correspond to the lyman alpha transition.


Due to the geometry of the Heliosphere-Astrosphere system, the redder side of the absorption can be attributed to our heliosphere whereas the bluer side of the absorption can be attributed to the astrosphere being investigated. My goal is to use a coupled kinetic-MHD code to simulate the space environment of the sun and observed star and compare the predicted absorption to the actual absorption. This will allow for an estimate of the environment near the stars observed which will inform habitability.