A molecular window into the mass loss history of Luminous Blue Variables

Luminous Blue Variables represent a very short stage in the life of some massive stars, characterized by significant variability, dense and steady winds, and occasional mass eruptions that rip off the outer stellar layers. By virtue of these processes, LBVs are often surrounded by large and heterogeneous circumstellar structures, like the remarkable Homunculus Nebula around Eta Car, that contain the evolutionary footprint of the parent star. Therefore, these nebulae have been comprehensively studied at optical, infrared and radio wavelengths, resulting in a very accurate portrait of their dust and ionized gas content. However, a crucial piece of the puzzle is missing: a possible molecular counterpart. Such a component was overlooked for decades, but now we know that, under certain conditions, molecules can thrive in the hostile outskirts of LBV stars, despite the hot temperatures and strong UV fields. By investigating this molecular component at (sub)millimeter wavelengths, we can complete the mass-loss record of these challenging sources, learning about the mechanisms behind the eruptions and disclosing their chemical peculiarities. This talk will present the most remarkable findings of a search for molecular gas associated with Galactic LBV stars, focusing on a series of previously undetected warm molecular rings. These structures, displaying unmistakable signs of CNO-processed material, suggest an evolutionary connection that extends beyond the LBV phase. We will discuss the origin of these structures and the role of LBVs as molecular polluters, shedding light on how the most massive stars contributed to the chemical enrichment of the early Universe.