Velocity spectrum of neutral H atoms for a nitrogen-dominated atmosphere for 7, 10, and 20 XUV. Neutral hydrogen is produced only due to charge exchange. Originally, the newly produced hydrogen atoms have velocities of their stellar wind predecessors (a Maxwellian distribution with a maximum at 330 km s⁻¹), but then this distribution is altered by the collisions with other atmospheric neutrals. This is the source of the little “bump” in the velocity spectrum at very low velocities and the main source of neutral H particles in the part of the spectrum with the positive velocities.