JWST-TST DREAMS: Quartz Clouds in the Atmosphere of WASP-17b
JWST-TST DREAMS: Quartz Clouds in the Atmosphere of WASP-17b
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DOI：
10.3847/2041-8213/acfc3b
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发表时间：
2023-10
期刊：
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通讯作者：
D. Grant;N. Lewis;H. Wakeford;N. Batalha;A. Glidden;J. Goyal;Elijah Mullens;R. MacDonald;E. May;Sara Seager;K. Stevenson;J. Valenti;C. Visscher;L. Alderson;N. Allen;C. Cañas;Knicole D. Col'on;M. Clampin;N. Espinoza;A. Gressier;Jingcheng Huang;Zifan Lin;D. Long;D. Louie;M. Peña-Guerrero;S. Ranjan;K. Sotzen;Daniel Valentine;Jay Anderson;W. Balmer;Andrea Bellini;Kielan K. W. Hoch;J. Kammerer;M. Libralato;C. M. Mountain;Marshall D. Perrin;L. Pueyo;E. Rickman;I. Rebollido;S. T. Sohn;R. P. van der Marel;L. Watkins
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作者：
D. Grant;N. Lewis;H. Wakeford;N. Batalha;A. Glidden;J. Goyal;Elijah Mullens;R. MacDonald;E. May;Sara Seager;K. Stevenson;J. Valenti;C. Visscher;L. Alderson;N. Allen;C. Cañas;Knicole D. Col'on;M. Clampin;N. Espinoza;A. Gressier;Jingcheng Huang;Zifan Lin;D. Long;D. Louie;M. Peña-Guerrero;S. Ranjan;K. Sotzen;Daniel Valentine;Jay Anderson;W. Balmer;Andrea Bellini;Kielan K. W. Hoch;J. Kammerer;M. Libralato;C. M. Mountain;Marshall D. Perrin;L. Pueyo;E. Rickman;I. Rebollido;S. T. Sohn;R. P. van der Marel;L. Watkins
云在迄今为止观测到的许多系外行星大气中普遍存在。对于过境的系外行星，我们知道是否存在云，因为它们使光谱特征静音，并引起波长相关的散射。虽然这些云的确切成分在很大程度上是未知的，但这些信息对于了解行星大气的化学和能量收支至关重要。在这项工作中，我们用JWST的中红外低分辨率光谱仪观测了热木星WASP-17 b的一次凌日，并产生了5 - 12 μm的透射光谱。这些波长使我们能够探测由于各种预测云种类的振动模式而引起的吸收。我们的透射光谱显示了以8.6 μm为中心的额外不透明度，详细的大气建模和检索将此特征识别为SiO2（s）（石英）云。SiO2（s）云模型在3.5-4.2σ时优于无云模型，在2.6σ时优于一般气溶胶处方。我们发现SiO2（s）云是由直径小于0.01 μm的小颗粒组成的，并向高空延伸。大气中的H2O也出现了枯竭，这一发现与富氧物质形成高温气溶胶的现象相一致。这项工作是我们的JWST望远镜科学家团队（JWST-TST）的一系列研究的一部分，在这些研究中，我们将使用保证时间观测通过多仪器光谱学（DREAMS）对系外行星大气进行深度侦察。
Clouds are prevalent in many of the exoplanet atmospheres that have been observed to date. For transiting exoplanets, we know if clouds are present because they mute spectral features and cause wavelength-dependent scattering. While the exact composition of these clouds is largely unknown, this information is vital to understanding the chemistry and energy budget of planetary atmospheres. In this work, we observe one transit of the hot Jupiter WASP-17b with JWST’s Mid-Infrared Instrument Low Resolution Spectrometer and generate a transmission spectrum from 5 to 12 μm. These wavelengths allow us to probe absorption due to the vibrational modes of various predicted cloud species. Our transmission spectrum shows additional opacity centered at 8.6 μm, and detailed atmospheric modeling and retrievals identify this feature as SiO2(s) (quartz) clouds. The SiO2(s) clouds model is preferred at 3.5–4.2σ versus a cloud-free model and at 2.6σ versus a generic aerosol prescription. We find the SiO2(s) clouds are composed of small ∼0.01 μm particles, which extend to high altitudes in the atmosphere. The atmosphere also shows a depletion of H2O, a finding consistent with the formation of high-temperature aerosols from oxygen-rich species. This work is part of a series of studies by our JWST Telescope Scientist Team (JWST-TST), in which we will use Guaranteed Time Observations to perform Deep Reconnaissance of Exoplanet Atmospheres through Multi-instrument Spectroscopy (DREAMS).