利用CPI-C进行巨系外行星的光学-近红外多波段测光分析与表征
Optical-NIR Multi-band Photometric Analysis and Characterization of Giant Exoplanets with CPI-C
AI总结：
本研究基于CPI-C的八波段观测能力，提出多波段测光法表征巨系外行星，结合可见光与近红外数据可更严格约束行星关键参数，支撑其反射光与热辐射的联合分析。
AI中文摘要：
我们提出了一种用于表征巨系外行星的多波段测光方法，这是冷行星成像日冕仪（Cool Planet Imaging Coronagraph, CPI-C）预期的核心科学成果之一。CPI-C拥有两个观测通道，覆盖可见光和近红外波长，每个通道配备四个宽带滤光片。我们计算每个滤光片通带内的行星-恒星光通量比以开展测光分析。对于在可见光波段观测到的冷行星，相关数据主要用于拟合整体光谱形状和甲烷诱导的调制，可探测金属丰度和云量依赖的光谱变化，同时约束反射光的光谱形状以及包含行星半径、轨道间距和轨道相位的综合标度关系。在探测热辐射的近红外波段，相关数据有助于更好地约束行星的基本参数，包括有效温度、半径、表面重力和质量。对于一个具有可测量反射光和热辐射分量的合成巨行星，结合VIS4+NIR4波段的数据能比单独使用任一滤光片组获得更严格的同目标约束，尤其是在行星半径和云沉降参数方面。我们的模拟纳入了真实的仪器通量、探测器噪声和残余散斑噪声，结果表明，从可见光到近红外波长的八波段设计可支持CPI-C科学观测中巨系外行星的反射光诊断、热辐射表征以及光学-近红外联合分析。
英文摘要：
We present a multi-band photometric approach to characterize giant exoplanets, which represents one of the anticipated core scientific outcomes of Cool Planet Imaging Coronagraph (CPI-C). CPI-C operates with two observational channels covering visible and near-infrared wavelengths, each equipped with four broadband filters. The planet--star flux ratio integrated over each filter bandpass is calculated for photometric analysis. For cool planets observed in the visible bands, the data are primarily used to fit the overall spectral shape and methane-induced modulation, providing sensitivity to metallicity- and cloud-dependent spectral variations while constraining the reflected-light spectral shape and the combined scaling involving planet radius, orbital separation, and orbital phase. In the near-infrared bands, which probe thermal emission, the data help to better constrain fundamental planetary parameters including the effective temperature, radius, surface gravity and mass. For a synthetic giant planet with measurable reflected-light and thermal-emission components, the combined VIS4+NIR4 data provide tighter same-target constraints than either filter set alone, especially for the planet radius and cloud sedimentation parameter. Our simulations incorporate realistic instrument throughput, detector noise, and residual speckle noise. The results demonstrate that the eight-band design spanning visible to near-infrared wavelengths supports reflected-light diagnostics, thermal-emission characterization, and joint optical--NIR analysis of giant exoplanets within CPI-C science observations.
