Speaker
Description
The presence of cold Jupiters may strongly influence the formation and survival of inner low-mass companions, yet the observational evidence remains incomplete. Radial-velocity (RV) surveys provide the most direct approach to probe this connection, enabling searches for short-period sub-Neptunes and super-Earths in systems already known to host long-period giants. Although high-precision, long-baseline RV datasets from instruments such as HARPS, HARPS-N, HIRES, and CARMENES, often complemented by Gaia astrometry, now allow simultaneous characterization of both outer and inner regions of exoplanetary systems, our knowledge remains incomplete, due to the observational difficulty to detect low-mass companions. Several surveys have revealed diverse system architectures: some cold Jupiter hosts harbor multiple compact low-mass planets, while others appear devoid of inner companions. Large-sample analyses combining recent and historical RV datasets are beginning to quantify the occurrence rate of inner low-mass planets in the presence of outer giants, probing dependencies on stellar mass, orbital separation, and eccentricity. Detection biases and observational limitations remain significant, but consistent trends are emerging, providing an empirical foundation for understanding how inner planetary systems coexist with massive outer companions. This review will summarize current observational efforts and statistical results from RV surveys, highlighting remarkable systems detected in such surveys, and delineating the emerging picture of inner low-mass planets discovered in the shadow of giants.
