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Webb Data Point to Thick Atmosphere on Ultra‑Hot Super‑Earth TOI‑561 b

A cooler‑than‑expected dayside suggests heat‑shifting gases above a global magma ocean.

Overview

  • JWST’s NIRSpec measured TOI‑561 b’s dayside near 3,200°F (1,800°C), far below the ~4,900°F (2,700°C) expected for a bare rock.
  • Researchers report the strongest evidence yet for a volatile‑rich atmosphere that absorbs radiation and redistributes heat.
  • The team proposes a magma–atmosphere equilibrium that continually exchanges gases with the molten surface, a “wet lava ball” scenario.
  • Alternative explanations such as magma‑only heat transport or a thin rock‑vapor layer cannot reproduce the observed cooling.
  • Observed under GO Program 3860 with >37 hours of continuous coverage, the ancient, iron‑poor system will be further analyzed to map temperatures and refine the atmosphere’s composition.