系外行星大气透射光谱图

一张天体物理数据可视化图，模拟超地球系外行星大气透射光谱，仿 Nature Astronomy 论文图表风格。主图为带误差棒的散点图：x 轴 "Wavelength (μm)"（0.5–5.0），y 轴 "Transit Depth (ppm)"；暗炭灰数据点，钴蓝平滑模型曲线叠加；淡蓝色带标注 H₂O（1.4/1.9 μm），淡红带标注 CO₂（2.7/4.3 μm），淡绿带标注 CH₄（3.3 μm）。右上角插图：小蓝行星轮廓凌日大橙恒星，光线示意。白色背景，坐标轴外向刻度，9pt 说明字体，matplotlib Nature 样式风格。

A clean astrophysics data-visualisation figure showing a simulated transmission spectrum of a super-Earth exoplanet atmosphere, styled like a panel from a Nature Astronomy paper. The main chart is a scatter plot with error bars: the x-axis is labelled "Wavelength (μm)" spanning 0.5 to 5.0, the y-axis is "Transit Depth (ppm)". Data points are small filled circles with vertical error bars in dark charcoal. A smooth model spectrum curve overlays the data in cobalt blue. Coloured shaded bands highlight molecular absorption features: water vapour (H₂O) in pale blue at 1.4 μm and 1.9 μm, carbon dioxide (CO₂) in pale red at 2.7 μm and 4.3 μm, methane (CH₄) in pale green at 3.3 μm. Each band is annotated with the molecule name. A miniature planetary transit geometry diagram appears as an inset at upper-right: a small blue planet silhouette crossing in front of a large orange star, with light rays indicated. Background: white publication background. Tick marks on axes are outward-pointing. Caption font 9 pt. The overall figure should look like it was produced in Python's matplotlib with a Nature stylesheet.