Measurement of Shifts in Line-of-Sight Velocities of Stellar Water Masers using Very Long Baseline Interferometry
Stellar water masers as observed with high spatial resolution of VLBI are expected to be very useful traces of detailed physics and kinematics in the mass-loss process of evolved stars on the basis of measurements of their spatial distribution, velocity profile and proper motions. We performed VLBI monitoring observations of water masers around a semiregular variable RT Vir and detected for the first time systematic shifts of line-of-sight velocities in time for several spatially distinguished water maser spots. In some strong water maser spots, the line-of-sight velocities linearly increased or decreased through successive observing sessions during four months. The absence of clear one-to-one correspondence between acceleration/deceleration and blue/red-shift of the maser spots is likely to imply the complicated nature of the real mass-loss process of the evolved star.
IAU Joint Discussion
- Pub Date: