Heliotail

The Interstellar Boundary Explorer (IBEX) is the first mission to remotely observe the heliosphere's global interaction with the local interstellar medium (LISM). Very recently, McComas et al. examined the heliotail for the first time. The summary of the heliotail observation from McComas et al. is that "the heliotail includes a broad low to mid-latitude structure, which has an excess of lower energy energetic neutral atoms (ENAs) and a deficit at higher energies, producing a relatively steep power law energy spectrum compared to the rest of the sky. The spatial arrangement of the ENA spectral index from the heliotail clearly reflects and is consistent with the latitudinal ordering of the solar wind over much of the solar cycle around solar minimum, with slow solar wind at low/midlatitudes and fast wind at high latitudes.