JWST/NIRSpec Transmission Spectrum of the Hazy Sub-Neptune GJ1214 b

GJ1214 b is one of the canonical sub-Neptunes that serves as a benchmark system over a decade. Despite the intensive observational efforts, however, the atmospheric compositions of GJ1214b remain elusive, as high-altitude clouds/hazes flatten the observed spectra and hinder further atmospheric characterizations. JWST has the potential to unveil the compositional detail of GJ1214b thanks to its unprecedent precision and ability to probe long wavelengths where clouds/hazes tend to be transparent. In this presentation, we will report the first JWST/NIRSpec G395H transmission spectrum of GJ1214b at 3—5 µm that was observed as a part of the MANATEE JWST GTO program. Previous and current atmospheric models have predicted the emergence of prominent CH₄ and CO₂ features even if existing HST and JWST MIRI LRS transmission spectra appear featureless. We will present the evidence of some spectral features in the observed spectrum and discuss the origin of them.