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Main Author: Taylor, Jake
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2504.15916
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author Taylor, Jake
author_facet Taylor, Jake
contents 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 $χ^{2}_ν$ 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 $χ^{2}_ν$ of 0.99. With only $\sim$2-$σ$ in favour of Gaussian features, I conclude no strong statistical evidence for spectral features.
format Preprint
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institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Are there Spectral Features in the MIRI/LRS Transmission Spectrum of K2-18b?
Taylor, Jake
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
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 $χ^{2}_ν$ 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 $χ^{2}_ν$ of 0.99. With only $\sim$2-$σ$ in favour of Gaussian features, I conclude no strong statistical evidence for spectral features.
title Are there Spectral Features in the MIRI/LRS Transmission Spectrum of K2-18b?
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2504.15916