Cloudy mornings and clear evenings on a gas giant exoplanet

• 成果类型: Article
• 署名作者: Mukherjee, Sagnick; Sing, David K.; Fu, Guangwei; Stevenson, Kevin B.; Schmidt, Stephen P.; Baskett, Harry; Mak, Mei Ting; McCreery, Patrick; Allen, Natalie H.; Bennett, Katherine A.; Christie, Duncan A.; Gascon, Carlos; Goyal, Jayesh; Hebrard, Eric; Lothringer, Joshua D.; Lopez-Morales, Mercedes; Lustig-Yaeger, Jacob; May, Erin M.; Mayorga, L. C.; Mayne, Nathan; Ramos Rosado, Lakeisha M.; Reggiani, Henrique; Rustamkulov, Zafar; Schlaufman, Kevin C.; Sotzen, Kristin S.; Thorngren, Daniel; Wang, Le-Chris; Zamyatina, Maria
• 署名单位: Johns Hopkins University; University of California System; University of California Santa Cruz; Arizona State University; Arizona State University-Tempe; Johns Hopkins University; Johns Hopkins University; Johns Hopkins University Applied Physics Laboratory; University of Exeter; University of Oxford; Max Planck Society; Harvard University; Smithsonian Institution; Institut d'Estudis Espacials de Catalunya (IEEC); National Institute of Science Education & Research (NISER); Homi Bhabha National Institute; Space Telescope Science Institute
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8075; 1095-9203
• DOI: 10.1126/science.adx5903
• 发表日期: 2026-05-21
• 页码: 858-862
• 关键词: molecular line lists; collision-induced absorption; rotation-vibration spectrum; OPTICAL-CONSTANTS; 3D SIMULATIONS; hd 189733b; hot; temperature; atmosphere; hubble

摘要

The spectra of exoplanet atmospheres are affected by aerosols (clouds and hazes) of uncertain origin. Proposed aerosol formation mechanisms include gas condensation or photochemical reactions. We measured the transmission spectrum of the tidally locked gas giant exoplanet WaSP- 94a b and identified asymmetry in its atmosphere. The morning limb is cooler and cloudy, whereas the evening limb is hotter and exhibits gaseous water absorption features. We interpret this difference as being due to the formation of cloud droplets near the morning limb, which evaporate during circulation to the evening limb. The dominant aerosols are clouds cycling between the day and night sides of the atmosphere, not photochemical hazes. The resulting asymmetry can severely bias chemical abundance measurements, unless limb- resolved spectroscopy is available.