Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM by Z. Rustamkulov et al. on Monday 21 November

Transmission spectroscopy of exoplanets has revealed signatures of water

vapor, aerosols, and alkali metals in a few dozen exoplanet atmospheres.

However, these previous inferences with the Hubble and Spitzer Space Telescopes

were hindered by the observations' relatively narrow wavelength range and

spectral resolving power, which precluded the unambiguous identification of

other chemical species$-$in particular the primary carbon-bearing molecules.

Here we report a broad-wavelength 0.5-5.5 $\mu$m atmospheric transmission

spectrum of WASP-39 b, a 1200 K, roughly Saturn-mass, Jupiter-radius exoplanet,

measured with JWST NIRSpec's PRISM mode as part of the JWST Transiting

Exoplanet Community Early Release Science Team program. We robustly detect

multiple chemical species at high significance, including Na (19$\sigma$),

H$_2$O (33$\sigma$), CO$_2$ (28$\sigma$), and CO (7$\sigma$). The non-detection

of CH$_4$, combined with a strong CO$_2$ feature, favours atmospheric models

with a super-solar atmospheric metallicity. An unanticipated absorption feature

at 4$\mu$m is best explained by SO$_2$ (2.7$\sigma$), which could be a tracer

of atmospheric photochemistry. These observations demonstrate JWST's

sensitivity to a rich diversity of exoplanet compositions and chemical

processes.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.10487v1