Speaker
Description
In this talk, I will present an interesting scientific case for GAIA NIR regarding the characterization of metal-rich RR Lyrae stars in the stellar disc. While RR Lyrae stars have traditionally been considered old and metal-poor population II stars, it is well known that metal-rich (up to solar values) RR Lyrae stars exist in the solar vicinity. Leveraging GAIA's capabilities (Gaia DR2 and Gaia DR3), we have discovered that these metal-rich RR Lyrae stars are distributed throughout the Galactic disk, extending beyond the Solar neighborhood.
The kinematics of these stars align with a young (less than 5 Gyr) thin-disc population, challenging conventional RR Lyrae formation scenarios. Our research suggests that significant mass-loss events in binary systems could produce a population of metal-rich RR Lyrae stars with ages consistent with the thin-disc populations. However, identifying RR Lyrae stars in binary systems remains a challenge.
In this context, GAIA NIR may be the perfect instrument to increase the number of observed RR Lyrae in the high-extinct regions of the Galactic disc. The combination of photometry and astrometry will fundamental to characterize such objects and confirm or not the proposed binary formation channel.
