A new study, published in Astronomy & Astrophysics journal, presents a detailed reanalysis of the multiplanetary system orbiting HD20794 (82 Eridani), a Sun-like star located just 19,7 light-years away. Utilizing state-of-the-art radial velocity (RV) techniques and improved stellar activity modeling, researchers have constrained the orbital parameters and masses of its suspected exoplanets with unprecedented precision while assessing the system’s dynamical stability.
The study incorporates next-generation RV data from instruments ESPRESSO (VLT) – which has been the foundation for several groundbreaking discoveries in the field of exoplanets, such as the confirmation of Proxima d – and HARPS, achieving sub-meter-per-second precision to disentangle planetary signals from stellar noise. This instrument has produced numerous significant scientific findings, including the identification of the first Super-Earth.
The authors identified a system consisting of three planets that orbit the solar-type star HD 20794 in August 2011. This star is bright and close, and HD 20794-d is a Super-Earth exoplanet which orbits that G-type star. The planet is located within the habitable zone of its star, positioning this system as a top candidate for upcoming atmospheric studies using direct imaging facilities. About six times the mass of Earth, the planet orbits “at the right distance from its star to sustain liquid water on its surface — a key ingredient for life as we know it.” The low level of this system’s activity find confirms the stability of HD 20794 and its suitability as a standard target for observations carried out by future facilities.
HD20794 exemplifies how modern RV techniques can breathe new life into “known” exoplanet systems. This system is a benchmark for testing how multiplanet systems emerge around Sun-like stars and serves as an important contribution to our understanding of exoplanetary systems by providing updated insights into their characteristics, dynamics, formation processes and potential for habitability.
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