Are there Spectral Features in the MIRI/LRS Transmission Spectrum of K2-18b?
2025/04/22 by Jake Taylor, Taylor, Jake · 11 voices · 6 citations
Engineering · #Astronomical Observations and Instrumentation #Gaussian #Gaussian process #Line (geometry) #Particle Accelerators and Free-Electron Lasers #Particle accelerators and beam dynamics #Spectral density #Spectral line #Spectral line shape #Spectral shape analysis #Spectrum (functional analysis) #Trispectrum
paper · pdf · doi:10.48550/arxiv.2504.15916
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2025/04/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract
Determining the composition of an exoplanet atmosphere relies on the presence of detectable spectral features. The strongest spectral features, including DMS, look approximately Gaussian. Here, I perform a suite of Gaussian feature analyses to find any statistically significant spectral features in the recently published MIRI/LRS spectrum of K2-18b (N. Madhusudhan et al. 2025). In N. Madhusudhan et al. 2025, they claim a 3.4-σ detection of spectral features compared to a flat line. In 5 out of 6 tests, I find the data preferred a flat line over a Gaussian model, with a χ2ν of 1.06. When centering the Gaussian where the absorptions for DMS and DMDS peak, I find ln(B) = 1.21 in favour of the Gaussian model, with a χ2ν of 0.99. With only ∼2-σ in favour of Gaussian features, I conclude no strong statistical evidence for spectral features.
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Discussions
- Nice to see this research note on K2-18b from @astrojake.bsky.social, which demonstrates that a flat line (i.e. no spectral features) is a good fit to the MIRI data. #exoplanet 🪐 🔭 arxiv.org/abs/250 [bsky, 50 points, 3 comments]
- Very cool video by David! I assume it was filmed before my paper: arxiv.org/abs/2504.15916, and before Welbanks & Nixon et al: arxiv.org/abs/2504.21788 came out. It’s great to see these discussions ha [bsky, 9 points, 1 comments]
- Wow, that was quick! Less than a week out and there's already a rebuttal to the K2-18b DMS detection arxiv.org/abs/2504.15916 [bsky, 6 points, 0 comments]
- #arXiv Are there Spectral Features in the MIRI/LRS Transmission Spectrum of K2-18b? https://arxiv.org/abs/2504.15916 The data preferred a flat line over a Gaussian model (with no statistical evidence [bsky, 2 points, 0 comments]
- Or maybe not arxiv.org/pdf/2504.15916 [bsky, 2 points, 0 comments]
- Madhusudhan wrote a press release that lied about his own paper, but even in the paper he did some statistical tomfoolery [See @astrojake.bsky.social's arxiv.org/abs/2504.15916 and Welbanks+ arxiv.org [bsky, 2 points, 1 comments]
- # arXiv Are there Spectral Features in the MIRI/LRS Transmission Spectrum of K2-18b? https:// arxiv.org/abs/2504.15916 The data preferred a flat line over a Gaussian model (with no statistical evidenc [mastodon, 0 points, 0 comments]
- #arXiv Are there Spectral Features in the MIRI/LRS Transmission Spectrum of K2-18b? https://arxiv.org/abs/2504.15916 The data preferred a flat line over a Gaussian model (with no statistical evidence [bsky, 0 points, 0 comments]
- Nice to see this research note on K2-18b from @astrojake.bsky.social, which demonstrates that a flat line (i.e. no spectral features) is a good fit to the MIRI data. #exoplanet 🪐 🔭 https://arxiv.org [bsky, 0 points, 0 comments]
- i thought the data was already available? Jake Taylor published this preprint. arxiv.org/pdf/2504.15916 [bsky, 0 points, 1 comments]
- "Even less evidence for life on K2-18b" https://arxiv.org/abs/2504.15916 [bsky, 0 points, 0 comments]
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