Pre-Supernova Multiple Giant Eruptions in Massive Stars

Massive stars can exhibit giant eruptions with high mass loss shortly before their explosion as a core-collapse Supernova. These multiple giant eruptions (MGEs) may have a commutative effect that brings the star to a different state, possible one that favors the explosion. To address this problem, we evolve a 100 solar mass star and initiate a series of three giant eruptions lasting one year each, testing different mass loss rates and different metallicities. Following each eruption, we track the recovery phase to examine the post-eruption behavior of the star and its recovery timescale. The MGEs lead to a decrease in luminosity, accompanied by a slight increase in temperature. Later, during the recovery phases as the star starts to retain its equilibrium state, its luminosity increases. The recovery time-scale varies significantly after each eruption for independent on the mass loss rate, but it is shorter for lower metallicities. For the higher mass-loss rates during the recovery phase, the outer layers of the star exhibit oscillations and undergo compression at higher metallicity. These oscillations are most likely a consequence of thermal imbalance in the outer envelope. This behavior at higher mass-loss rates also suggests that the thermal readjustments during recovery may create favorable conditions for a subsequent eruption of the star.