Overview
- The paper delivers the first robust mass measurements for all four planets in the ~20‑million‑year‑old system using transit‑timing variations.
- The worlds span roughly five to 10 Earth radii yet only five to 15 Earth masses, implying densities comparable to polystyrene foam.
- Recovery of a previously missed transit for the outer planet pinned down its orbital period and unlocked the full dynamical solution.
- Analysis shows substantial atmospheric loss under intense irradiation, with the planets expected to contract into super‑Earths and sub‑Neptunes over time.
- The resonant-like configuration provides a rare benchmark for models linking young, inflated planets to the compact sub‑Neptune systems common across the galaxy.