About half of the stars with a low to intermediate initial mass are born with a companion. However, when these stars evolve to their asymptotic giant branch (AGB), the fraction of detected binaries is scarce. The cause of this disparity is primarily due to the AGB bright and variable photosphere, which challenges traditional binary detection techniques.
Constraining the interaction mechanisms of AGB binaries is, nevertheless, crucial to understanding how they shape their wind morphology and the formation of their direct descendants.
In this talk, I will present our multi-instrumental study of the system V Hydrae, identified as the first spectroscopic binary system made up of a pulsating carbon-rich AGB star. I will highlight how combining the resolving power of complementary observational techniques (among them, decade-long monitoring with the HERMES spectrograph and infrared interferometry with the VLTI/MATISSE instrument) can unveil the presence of a companion by its impact on the gaseous outflow and the dust distribution at different scales. This study provides additional evidence of the connection between a binary companion and the bipolar morphology of radio nebulae.
I will then discuss the remaining open questions regarding the origin of periodic obscuration events and conclude by comparing the system properties with those of the other few characterized AGB binaries.
A search for AGB binaries : the multi-instrumental study of V Hydrae system
Mardi 8 juillet 2025
à
10h30
Salle de conférence du bâtiment 17 sur le site de Meudon
