LTT 9779 b enters the Codex as a castaway of the Neptunian desert, an ultra-hot Neptune racing around a Sun-like G-type star about 262 light-years away. Some 4.7 × Earth in radius and nearly 29 Earth masses, it circles its star in just 19 hours, its dayside roasting above 2,000 K where most worlds its size would have been stripped to bare rock. Found by TESS in 2020, it proved astonishingly bright, casting back a large share of the starlight that strikes it. JWST later mapped gleaming silicate clouds massed over its western dayside, likely condensing where winds carry cooler air in from the night. Hostile to life, it endures as a mirror-bright survivor of a realm that should be empty.
