Overview
- Spectroscopy with JWST’s NIRSpec IFU reveals hydrogen sulfide in the atmosphere of HR 8799 c, with the team reporting similar chemistry likely across the system’s inner giants.
- The three inner planets show heavy-element enrichment relative to their host star, a chemical signature consistent with growth by accreting solids rather than star-like collapse.
- Researchers developed new data-extraction techniques to isolate planetary spectra about 10,000 times fainter than the star and built refined atmospheric models to identify rare molecular features.
- The findings, published in Nature Astronomy, indicate that core accretion can operate for 5–10 Jupiter-mass planets on wide orbits of roughly 15–70 AU in the HR 8799 system about 133 light-years away.
- Co-authors say the result challenges older formation models and sets a new benchmark for testing massive companions with JWST using refractory-element tracers.