Study of the last stages of stellar evolution

My research focus on the genesis of asymmetric mass-loss of low- and intermediate- mass stars (<8 M_sun), in the evolution from the asymptotic giant branch (AGB) toward the planetary nebula phase. Therefore, it would be necessary to study the first stages when bipolar and multipolar ejections appear in evolved stars. I carried out radio observations of continuum and maser emissions in early and late post-AGB stars. While radio continuum observation can trace the morphology of the ionized gas in young PNe, maser observation is a powerful tool to study with the highest angular resolution the molecular gas around evolved stars, because masers are characterized by a high brightness and compactness. We would be able to study the physical conditions, morphology, and kinematics of the gas around these stars. Moreover, since maser emission is often linearly and circularly polarized, provides information about the magnetic field strength and its orientation, helping to understand its potential role in the shaping process of PNe.