Does the atmosphere of K2-18 b contain dimethyl sulfide? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
Does the atmosphere of K2-18 b contain dimethyl sulfide?
Plain
A team using JWST reported hints of dimethyl sulfide, a gas made on Earth almost only by marine life, on the planet K2-18 b. Other teams analyzing the same data find no reliable signal.
Precise · changed · core
Revision 1: K2-18 b is a temperate sub-Neptune ($R \sim 2.6 R_{\mathrm{earth}}, M \sim 9 M_{\mathrm{earth}}$) orbiting an M dwarf, with CH4 and CO2 detected by JWST in 2023. Determine whether dimethyl sulfide (and dimethyl disulfide) is present at $\ge 5\sigma$ in JWST NIRISS, NIRSpec and MIRI spectra, and if present, whether abiotic photochemistry or delivery can produce the inferred abundance.
Revision 2: K2-18 b is a temperate sub-Neptune ($R \sim 2.6 R_{\mathrm{earth}}, M \sim 9 M_{\mathrm{earth}}$) orbiting an M dwarf, with $\mathrm{CH_4}$ and $\mathrm{CO_2}$ detected by JWST in 2023. Determine whether dimethyl sulfide (and dimethyl disulfide) is present at $\ge 5\sigma$ in JWST NIRISS, NIRSpec and MIRI spectra, and if present, whether abiotic photochemistry or delivery can produce the inferred abundance.
Settled by
Additional JWST transits analyzed by independent pipelines with agreed systematics treatment, reaching a $5\sigma$ detection or an upper limit below the claimed abundance.
Kind
well-posed
Answer type
yes-no
References
(empty)
Literature status
contested
Status note
A 2025 MIRI analysis reported about $3\sigma$ evidence for dimethyl sulfide or dimethyl disulfide; independent 2025 reanalyses found no statistically significant evidence, and 2026 papers model the spectrum without dimethyl sulfide.
Posed since
2023

Decisions