Episodicity in accretion-ejection processes associated with IRAS 15398-3359

Context . The protostar IRAS 15398-3359 is associated with a bipolar molecular outflow ejected in an nearly northeast-southwest (NE–SW) direction, which has been extensively studied. Previous episodic accretion events have been suggested by this source. Furthermore, the analysis of the morphology and kinematics of the molecular outflow revealed the presence of four 12 CO (2–1) bipolar elliptical shock-like structures identified in both lobes. These structures seem to trace different ejections inclined ~10° from each other on the plane of the sky. This led to the hypothesis that the outflow axis likely precesses and launches material episodically. Aims . Since several authors reached the conclusion of the same episodicity scenario by independent observations, IRAS 15398-3359 has become an ideal target to empirically analyze the relationship between accretion and ejection processes. Methods . We analyzed ALMA archive observations in Band 6, revealing the presence of low-velocity (