Context. RR Lyrae stars are excellent tracers of the oldest stars (ages≳ 9–10 Gyr) and
standard candles for measuring the distance to stellar systems that are mainly composed of …

We discuss the use and importance of pulsating variable stars as population tracers in Local
Group galaxies. Among bright variable crossing the classical instability strip, we mostly focus …

Context. Classical Cepheids (CCs) are solid distance indicators and tracers of young stellar
populations. Dating back to the beginning of the 20th century, they have been safely …

Abstract The Transiting Exoplanet Survey Satellite (TESS) space telescope is collecting
continuous, high-precision optical photometry of stars throughout the sky, including …

RR Lyrae variables are excellent Population II distance indicators thanks to their well-
defined period–luminosity relations (PLRs) at infrared wavelengths. We present results of …

Context. Classical Cepheids are the most popular distance indicators and tracers of young
stellar populations. The key advantage is that they are bright and they can be easily …

We discuss the largest and most homogeneous spectroscopic data set of field RR Lyrae
variables (RRLs) available to date. We estimated abundances using both high-resolution …

We present new period-ϕ 31-[Fe/H] relations for first-overtone RRL stars (RRc), calibrated
over a broad range of metallicities (− 2.5≲[Fe/H]≲ 0.0) using the largest currently available …

This investigation is mainly focused on the LSST Survey Strategy Optimization process, a
bottom-up approach that turned out to be quite effective in involving the scientific community …

Context. RR Lyrae stars are excellent tracers of the old population II due to their period-
luminosity (PL) and period-luminosity-metallicity (PLZ) relations. While these relations have …