近日，美国约翰斯·霍普金斯大学Sagnick Mukherjee团队报道了在一颗巨大的气体系外行星上，晨侧多云，昏侧晴朗。这一研究成果于2026年5月21日发表在《科学》杂志上。

系外行星大气光谱会受到来源不确定的气溶胶（云和霾）的影响。已提出的气溶胶形成机制包括气体凝结或光化学反应。

研究组测量了潮汐锁定的气态巨行星WASP-94A b的透射光谱，并发现其大气中存在不对称性。晨侧大气较冷且多云，而昏侧大气较热，并显示出气态水的吸收特征。研究组将这一差异解释为晨侧附近形成了云滴，这些云滴在环流至昏侧的过程中蒸发。主导的气溶胶是在大气昼夜两侧之间循环的云，而非光化学产生的霾。这种不对称性可能会严重偏差化学丰度的测量结果，除非采用可分辨晨昏侧的光谱技术。

附：英文原文

Title: Cloudy mornings and clear evenings on a gas giant exoplanet

Author: Sagnick Mukherjee, David K. Sing, Guangwei Fu, Kevin B. Stevenson, Stephen P. Schmidt, Harry Baskett, Mei Ting Mak, Patrick McCreery, Natalie H. Allen, Katherine A. Bennett, Duncan A. Christie, Carlos Gascón, Jayesh Goyal, éric Hébrard, Joshua D. Lothringer, Mercedes López-Morales, Jacob Lustig-Yaeger, Erin M. May, L. C. Mayorga, Nathan Mayne, Lakeisha M. Ramos Rosado, Henrique Reggiani, Zafar Rustamkulov, Kevin C. Schlaufman, Kristin S. Sotzen, Daniel Thorngren, Le-Chris Wang, Maria Zamyatina

Issue&Volume: 2026-05-21

Abstract: 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.

DOI: adx5903

Source: https://www.science.org/doi/10.1126/science.adx5903