Dormant black holes in X-ray transients can be identified by the presence of broad Hα emission lines from quiescent accretion discs. Unfortunately, short-period cataclysmic variables can also produce broad Hα lines, especially when viewed at high inclinations, and are thus a major source of contamination. Here we compare the full width at half maximum (FWHM) and equivalent width (EW) of the Hα line in a sample of 20 quiescent black hole transients and 354 cataclysmic variables (305 from SDSS I to IV) with secure orbital periods (Porb) and find that: (1) FWHM and EW values decrease with Porb

The TESS (Transiting Exoplanet Survey Satellite) mission has discovered many exoplanet candidates that need to be confirmed and characterized from the ground. One of them orbits Ross 176, a K-type dwarf star, where we have identified a promising hot “water-world” candidate. Using spectroscopic observations with the CARMENES instrument, we confirmed the planetary nature of the signal detected by TESS and estimated the planet’s mass. To improve the analysis, we applied an advanced statistical method called Gaussian Process, which allowed us to separate the star’s own variability (quite strong

Sub-Neptunes - planets larger than Earth but smaller than Neptune - are the most common type of planet in our Galaxy, yet they are entirely absent from our own Solar System. This absence makes them a major focus for astronomers seeking to understand planetary formation and evolution. We recently conducted an international study, as part of the THIRSTEE project, to characterize two such planets orbiting very similar small, cool stars known as M dwarfs: TOI-521 and TOI-912 . THIRSTEE is an observational-based program that aims to shed light on the sub-Neptune population by providing an