长基线光学干涉测量中的寄生干扰：热彗星类行星探测的要求
Parasitic Interference in Long Baseline Optical Interferometry: Requirements for Hot Jupiter-like Planet Detection
摘要：
光学干涉测量中的可观测量，即复可见度的模和相位，可能被叠加在真实条纹图案上的寄生条纹所破坏。这些条纹是由于干涉仪内部的杂散光效应产生的干涉现象。我们开发了一种分析方法，以更好地理解这种现象时，杂散光导致光束之间的串扰。我们推导出寄生干涉显著影响干涉相位，从而影响相关的观测量，包括微分相位和闭合相位。耦合到梁之间的活塞的寄生通量的量似乎是非常有影响力的这种退化。例如，考虑L波段（$λ=3.5\:μ$ m）中从$λ/500$到$λ/5$的点状源和活塞，总通量的约1%的寄生通量产生达到本征相位的至多三分之一的寄生相位。活塞可能有不同的起源（仪器稳定性、大气扰动.），因此放大了寄生干扰的影响。根据空间或地面活塞校正的规范（分别为$λ/500\approx 2$ nm和$λ/30\approx 100$ nm），探测热的类彗星行星是目前地面干涉仪最具挑战性的目标之一，将寄生辐射限制在入射强度的5%左右。这是通过考虑不同类型的热木星合成光谱来评估的。否则，如果不使用条纹跟踪，则对于等于$λ$ /15的活塞误差，对具有类太阳恒星的典型热类彗星系统的探测将允许0.01\%的寄生强度的最大水平。如果没有精确地观察到条纹跟踪规范，那么看起来寄生强度的允许水平显著降低并且可能阻止检测。与此同时，在这种精度水平下，通过参考星校准寄生相位似乎非常困难。此外，由于寄生相位是一个对象相关的量，使用一个假设的相位算盘，直接从一个给定的寄生通量水平的寄生相位，也是不可能的。本文介绍了在仪器设计阶段为限制或防止这种寄生干扰而实施的一些仪器解决方案。
英文摘要：
The observable quantities in optical interferometry, which are the modulus and the phase of the complex visibility, may be corrupted by parasitic fringes superimposed on the genuine fringe pattern. These fringes are due to an interference phenomenon occurring from straylight effects inside an interferometric instrument. We developed an analytical approach to better understand this phenomenon when straylight causes crosstalk between beams. We deduced that the parasitic interference significantly affects the interferometric phase and thus the associated observables including the differential phase and the closure phase. The amount of parasitic flux coupled to the piston between beams appears to be very influential in this degradation. For instance, considering a point-like source and a piston ranging from $λ/500$ to $λ/5$ in L band ($λ=3.5\:μ$m), a parasitic flux of about 1\% of the total flux produces a parasitic phase reaching at most one third of the intrinsic phase. The piston, which can have different origins (instrumental stability, atmospheric perturbations, ...), thus amplifies the effect of parasitic interference. According to specifications of piston correction in space or at ground level (respectively $λ/500\approx 2$nm and $λ/30\approx 100$nm), the detection of hot Jupiter-like planets, one of the most challenging aims for current ground-based interferometers, limits parasitic radiation to about 5\% of the incident intensity. This was evaluated by considering different types of hot Jupiter synthetic spectra. Otherwise, if no fringe tracking is used, the detection of a typical hot Jupiter-like system with a solar-like star would admit a maximum level of parasitic intensity of 0.01\% for piston errors equal to $λ$/15. If the fringe tracking specifications are not precisely observed, it thus appears that the allowed level of parasitic intensity dramatically decreases and may prevent the detection. In parallel, the calibration of the parasitic phase by a reference star, at this accuracy level, seems very difficult. Moreover, since parasitic phase is an object-dependent quantity, the use of a hypothetical phase abacus, directly giving the parasitic phase from a given parasitic flux level, is also impossible. Some instrumental solutions, implemented at the instrument design stage for limiting or preventing this parasitic interference, appears to be crucial and are presented in this paper.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
