Monitoring of the polarized H2O maser emission around the massive protostars W75N(B)-VLA 1 and W75N(B)-VLA 2

Several radio sources have been detected in the high-mass star-forming region W75N(B), among them the massive young stellar objects VLA 1 and VLA 2 are of great interest. These are thought to be in different evolutionary stages. In particular, VLA 1 is at the early stage of the photoionization and it is driving a thermal radio jet, while VLA 2 is a thermal, collimated ionized wind surrounded by a dusty disk or envelope. In both sources 22 GHz H₂O masers have been detected in the past. Those around VLA 1 show a persistent linear distribution along the thermal radio jet and those around VLA 2 have instead traced the evolution from a non-collimated to a collimated outflow over a period of ∼20 years. The magnetic field inferred from the H₂O masers showed a rotation of its orientation according to the direction of the major-axis of the shell around VLA 2, while it is immutable around VLA 1.