论文标题
与JWST Niriss的系外行星WASP-39B的早期发行科学
Early Release Science of the exoplanet WASP-39b with JWST NIRISS
论文作者
论文摘要
传输光谱学提供了有关大气特性的洞察力，因此可以洞悉过渡系外行星的形成历史，物理和化学。但是，从传输光谱获得大气特性的精确推断需要同时测量各种化学物种的多种光谱吸收特征的强度和形状。鉴于先前的观测值的精度和波长覆盖范围，这是具有挑战性的。在这里，我们介绍了使用JWST上的Niriss仪器的SOSS模式获得的土星质量系外行星WASP-39B的传输光谱。该光谱跨越$0.6-2.8μ$ m的波长，并揭示了多个吸水带，钾共振双线以及云的特征。 The precision and broad wavelength coverage of NIRISS-SOSS allows us to break model degeneracies between cloud properties and the atmospheric composition of WASP-39b, favoring a heavy element enhancement ("metallicity") of $\sim 10 - 30 \times$ the solar value, a sub-solar carbon-to-oxygen (C/O) ratio, and a solar-to-super-solar potassium-to-oxygen （k/o）比率。观察结果最好通过波长依赖性的非灰色云来解释，而无与伦比的覆盖范围是地球的终结者。
Transmission spectroscopy provides insight into the atmospheric properties and consequently the formation history, physics, and chemistry of transiting exoplanets. However, obtaining precise inferences of atmospheric properties from transmission spectra requires simultaneously measuring the strength and shape of multiple spectral absorption features from a wide range of chemical species. This has been challenging given the precision and wavelength coverage of previous observatories. Here, we present the transmission spectrum of the Saturn-mass exoplanet WASP-39b obtained using the SOSS mode of the NIRISS instrument on the JWST. This spectrum spans $0.6 - 2.8 μ$m in wavelength and reveals multiple water absorption bands, the potassium resonance doublet, as well as signatures of clouds. The precision and broad wavelength coverage of NIRISS-SOSS allows us to break model degeneracies between cloud properties and the atmospheric composition of WASP-39b, favoring a heavy element enhancement ("metallicity") of $\sim 10 - 30 \times$ the solar value, a sub-solar carbon-to-oxygen (C/O) ratio, and a solar-to-super-solar potassium-to-oxygen (K/O) ratio. The observations are best explained by wavelength-dependent, non-gray clouds with inhomogeneous coverage of the planet's terminator.
