  High-energy stellar irradiation can photoevaporate planetary atmospheres,
which can be observed in spectroscopic transits of hydrogen lines. For the
exoplanet HD189733b, multiple observations in the Ly-$\alpha$ line have shown
that atmospheric evaporation is variable, going from undetected to enhanced
evaporation in a $1.5$-year interval. Coincidentally or not, when HD189733b was
observed to be evaporating, a stellar flare had just occurred 8h prior to the
observation. This led to the question of whether this temporal variation in
evaporation occurred due to the flare, an unseen associated coronal mass
ejection (CME), or even the effect of both simultaneously. In this work, we
investigate the impact of flares (radiation), winds, and CMEs (particles) on
the atmosphere of HD189733b using 3D radiation hydrodynamic simulations of
atmospheric evaporation that self-consistently include stellar photon heating.
We study four cases: first- the quiescent phase of the star including stellar
wind, second- a flare, third- a CME, and fourth- a flare that is followed by a
CME. Compared to the quiescent case, we find that the flare alone increases the
evaporation rate by only 25%, while the CME leads to a factor of 4 increase in
escape rate. We calculate Ly-$\alpha$ synthetic transits and find that the
flare alone cannot explain the observed high blueshifted velocities seen in the
Ly-$\alpha$ observation. The CME, however, leads to an increase in the velocity
of the escaping atmosphere, enhancing the transit depth at high blueshifted
velocities. While the effects of CMEs show a promising potential to explain the
blueshifted line feature, our models are not able to fully explain the
blueshifted transit depths, indicating that they might require additional
physical mechanisms.
