Juq-154 Access

The RV solution indicates an eccentricity of e = 0.04 ± 0.01, implying only modest seasonal variations. Dynamical simulations (N‑body integrations spanning 10⁸ yr) show the orbit is dynamically stable, with no resonant perturbations from the distant companion star (a M‑type dwarf at 210 AU) or any detected interior planets.

The planet’s near‑Earth insolation and low stellar activity suggest that JUQ‑154 could retain a primordial hydrogen envelope for billions of years. Yet the measured atmospheric composition indicates a secondary, outgassed atmosphere, perhaps generated by volcanic activity. This dual‑origin scenario provides a natural laboratory for testing models of atmospheric escape, mantle degassing, and photochemistry. JUQ-154

Mid‑infrared observations with JWST’s MIRI captured a secondary eclipse depth of 35 ppm, translating to a dayside brightness temperature of 298 K. Phase‑curve data reveal a modest day–night temperature contrast (~10 K), implying efficient heat redistribution, likely mediated by a substantial atmosphere and possibly an oceanic heat sink. The RV solution indicates an eccentricity of e = 0