Research on exoplanets is one of the fastest-growing fields in modern astrophysics. Increasingly powerful telescopes, cameras, and spectrographs make it possible to study a growing number of planetary systems. Transit observations and radial-velocity measurements are among the most common methods, providing complementary information when combined. For systems showing transits and precise radial-velocity signals, the Rossiter–McLaughlin effect can be observed. Analyzing this effect determines the projected angle between a planet’s orbital axis and its host star’s rotational axis (the projected stellar obliquity). This helps identify plausible formation and evolutionary scenarios, especially for hot Jupiters—giant planets orbiting very close to their stars, absent in our Solar System. High-resolution instruments regularly observe exoplanets, but not all data are processed or published immediately. Publicly released archives allow access to such observations. The main goal of this thesis was to find high-quality archived observations of systems where the Rossiter–McLaughlin effect can be measured, but has either not been analyzed or shows significant discrepancies. These were processed to determine the projected stellar obliquity and propose formation scenarios. A secondary objective was to identify candidates for follow-up observations with larger telescopes. Altogether, this work aims to shed light on how planetary systems emerge. Understanding planet formation is essential not only for explaining our Solar System’s history, but also for addressing the fundamental question of how life can arise in the universe.