Using numerical model calculations, we the transient heating effect from magnetospheric charged particle precipitation as proposed by Baker et al. (1987). Under extreme circumstances, the transient temperature increase may reach 1 K if the heating duration lasts more than one minute and the energy influx reaches 104 ergs/cm2/s. Otherwise, the expected temperature rise should be substantially smaller (ΔT/0.05 K). From this point of view, optical observations capable of differentiating various degrees of particle irradiation effect (i.e., modification of optical properties of surface dust layer and/or regolith structure) might be more appropriate to pinpoint signature of Mercury's auroral zones. ¿ American Geophysical Union 1987