AI 中文总结
该研究针对类金星系外行星，构建含固体自转与纬向风的反射光速度模型，发现大气超自转可模拟快速行星自转的虚假自旋特征，提出通过多光谱示踪剂的高度依赖信号打破简并，为相关观测提供方法依据。
AI 中文摘要
对类地系外行星的直接成像可通过时间分辨光度测量和高色散光谱实现自转与大气特征的表征。然而，从反射光推断出的速度场并不一定对应固体行星的自转，而是对应光子出射层的运动。金星为这种模糊性提供了太阳系内的关键范例：固体行星自转缓慢，而云层高度的大气则呈现超自转，周期仅为数天。本文研究快速行星自转与大气超自转之间的观测简并性，构建包含固体自转、纬向风及相位依赖光照的盘积分反射光速度模型。结果表明，对于探测窄压力范围的单个光谱示踪剂，其纬度依赖与固体自转相似的纬向风场可精确模拟快速自转行星的谱线轮廓；该简并性可通过测量视自转速度随波长或谱线形成压力的变化来打破。对于类金星风廓线，视周期可从低层大气的数百天变化至云层顶部的约4-5天。本文估算了测量这种垂直切变所需的分辨率和信噪比，指出大气超自转最可靠的诊断并非单一的v sin i值，而是跨多个光谱示踪剂的与高度相关的“虚假自旋”特征。这些结果对利用宜居世界天文台（Habitable Worlds Observatory）及配套高色散设备解释类金星世界的自转测量具有直接意义。
英文摘要
Direct imaging of terrestrial exoplanets will enable rotational and atmospheric characterization through time-resolved photometry and high-dispersion spectroscopy. However, the velocity field inferred from reflected light does not necessarily correspond to the rotation of the solid planet, but rather to the motion of the layer from which the photons emerge. Venus provides a crucial Solar System example of this ambiguity: the solid planet rotates slowly, whereas the cloud-level atmosphere exhibits superrotation with a period of only several days. Here we investigate the observational degeneracy between rapid planetary rotation and atmospheric superrotation. We construct a disk-integrated reflected-light velocity model that includes solid-body rotation, zonal winds, and phase-dependent illumination. We show that, for a single spectral tracer probing a narrow range of pressures, a zonal wind field whose latitude dependence is similar to solid-body rotation can exactly mimic the line profile of a rapidly rotating planet. The degeneracy can be broken by measuring the apparent rotational velocity as a function of wavelength or line formation pressure. For a Venus-like wind profile, the apparent period can vary from hundreds of days in the lower atmosphere to $\sim$4--5~days at the cloud deck. We estimate the resolving power and signal-to-noise ratio required to measure this vertical shear. The most robust diagnostic of atmospheric superrotation is not a single value of $v \sin i$, but an altitude-dependent ``false spin'' signature across multiple spectral tracers. These results have direct implications for interpreting rotational measurements of Venus-like worlds with the Habitable Worlds Observatory and complementary high-dispersion facilities.
Comments12 pages, 5 figures, accepted for publication in the Astronomical Journal
