Speaker
Description
The unique capabilities of the VLTI and ALMA instruments allow us to study the poorly constrained mass-loss process of AGB stars and red supergiants (RSGs). For stars of suitable size, VLTI can resolve their surface and dust formation zone at high spatial resolution, while ALMA can also provide high-resolution kinematical information.
In this work, we exploit the capabilities of both instruments when used together. For a sample of AGB stars, we obtained imaging observations in near-infrared with VLTI-PIONIER and VLTI-MATISSE, as well as high-frequency vibrational and rotational transitions of SiO masers (J=6-5, 7-6) with ALMA at the longest baselines. Combined, we can trace features from the stellar surface out into the dust formation zone and uniquely test and further constrain 1D and 3D models. Meanwhile, these are some of the first SiO maser observations at this high frequency and high spatial resolution. The enhanced maser position accuracy, thanks to high S/N component fitting, unveils unexpected maser structures.
I will also briefly discuss our recent results on AGB and RSG stars using VLTI-GRAVITY time series observations. Namely, I will demonstrate that we can constrain their pulsation properties, while we can also unveil their interacting companions and determine orbital parameters.