法国城市大学的 Dyrek, Achrne、荷兰空间研究所的 Min, Michiel 和比利时鲁汶大学的 Decin, Leen 等人合作，在研究海王星的成分中取得新进展。他们在温暖的海王星中探测到 SO₂ 和硅酸盐云团，但没有探测到CH₄。相关论文于2023年11月15日发表在《自然》杂志上。

研究团队报道了使用 JWST 的中红外仪器(MIRI)，在 WASP-107b 的透射光谱中，在 7.35 μm 和 8.69 μm 探测到两个二氧化硫的9σ探测基本振动波段。这一发现将 WASP-107b 确定为是第二颗具有光化学的受辐射的系外行星，将表现出检测到的光化学的系外行星的温度范围从大约1，200 K扩展到大约740 K。此外，光谱分析揭示了硅酸盐云的存在，与更简单的云设置相比，硅酸盐云更受青睐(~ 7σ)。此外，检测到水(~ 12σ)，但没有检测到甲烷。这些发现提供了不平衡化学的证据，并表明一个具有超级太阳金属丰度的动态活跃大气。

据介绍，WASP-107b 是一颗温暖的(约 740 k)的凌日行星，其扩展的大气层正在被侵蚀，质量与海王星相似，约 30.5 M_⊕，半径与木星相似，约 0.94 R_J。先前的观测表明，在 WASP-107b 的大气中存在水蒸气和厚厚的高空冷凝层。最近，光化学产生的二氧化硫(SO₂)在一个热的(约 1200 K)土星质量行星的大气中被检测到，来自 4.05 μm 附近的透射光谱学，但是对于低于约1,000 K 的温度，硫被预测优选形成硫同位素异形体，而不是 SO₂。

附：英文原文

Title: SO₂, silicate clouds, but no CH₄ detected in a warm Neptune

Author: Dyrek, Achrne, Min, Michiel, Decin, Leen, Bouwman, Jeroen, Crouzet, Nicolas, Mollire, Paul, Lagage, Pierre-Olivier, Konings, Thomas, Tremblin, Pascal, Gdel, Manuel, Pye, John, Waters, Rens, Henning, Thomas, Vandenbussche, Bart, Ardevol Martinez, Francisco, Argyriou, Ioannis, Ducrot, Elsa, Heinke, Linus, Van Looveren, Gwenael, Absil, Olivier, Barrado, David, Baudoz, Pierre, Boccaletti, Anthony, Cossou, Christophe, Coulais, Alain, Edwards, Billy, Gastaud, Ren, Glasse, Alistair, Glauser, Adrian, Greene, Thomas P., Kendrew, Sarah, Krause, Oliver, Lahuis, Fred, Mueller, Michael, Olofsson, Goran, Patapis, Polychronis, Rouan, Daniel, Royer, Pierre, Scheithauer, Silvia, Waldmann, Ingo, Whiteford, Niall, Colina, Luis, van Dishoeck, Ewine F., Ostlin, Gran, Ray, Tom P., Wright, Gillian

Issue&Volume: 2023-11-15

Abstract: WASP-107b is a warm (~740 K) transiting planet with a Neptune-like mass of~30.5 M⊕ and Jupiter-like radius of~0.94 RJ  whose extended atmosphere is eroding . Previous observations showed evidence for water vapour and a thick high-altitude condensate layer in WASP-107b’s atmosphere. Recently, photochemically produced sulphur dioxide (SO2) was detected in the atmosphere of a hot (~1,200 K) Saturn-mass planet from transmission spectroscopy near 4.05 μm, but for temperatures below~1,000 K sulphur is predicted to preferably form sulphur allotropes instead of SO2 . Here we report the 9σ-detection of two fundamental vibration bands of SO2, at 7.35 μm and 8.69 μm, in the transmission spectrum of WASP-107b using the Mid-Infrared Instrument (MIRI) of the JWST. This discovery establishes WASP-107b as the second irradiated exoplanet with confirmed photochemistry, extending the temperature range of exoplanets exhibiting detected photochemistry from~1,200 K down to~740 K. Additionally, our spectral analysis reveals the presence of silicate clouds, which are strongly favoured (~7σ) over simpler cloud setups. Furthermore, water is detected (~12σ), but methane is not. These findings provide evidence of disequilibrium chemistry and indicate a dynamically active atmosphere with a super-solar metallicity.

DOI: 10.1038/s41586-023-06849-0

Source: https://www.nature.com/articles/s41586-023-06849-0