The Transit Timing Variation (TTV) technique is a powerful dynamical tool to measure exoplanetary masses by analysing transit light curves. We assessed the transit timing performances of the Ariel Fine Guidance Sensors (FGS1/2) based on the simulated light curve of a bright, 55 Cnc, and faint, K2-24, planet-hosting star. We estimated through a Markov-Chain Monte-Carlo analysis the transit time uncertainty at the nominal cadence of 1 second and, as a comparison, at a 30 and 60-s cadence. We found that at the nominal cadence Ariel will be able to measure the transit time with a precision of about 12s and 34s, for a star as bright as 55 Cnc and K2-24, respectively. We then ran dynamical simulations, also including the Ariel timing errors, and we found an improvement on the measurement of planetary masses of about 20-30% in a K2-24-like planetary system through TTVs. We also simulated the conditions that allow us to detect the TTV signal induced by an hypothetical external perturber within the mass range between Earth and Neptune using 10 transit light curves by Ariel.

过境时间变化（TTV）技术是一种功能强大的动力学工具，可通过分析过境光曲线来测量系外行星质量。我们根据一颗明亮的55 Cnc和昏暗的K2-24行星托管恒星的模拟光曲线，评估了Ariel精细制导传感器（FGS1 / 2）的飞行计时性能。我们通过Markov-Chain蒙特卡洛分析法估计了标称节奏为1秒时的渡越时间不确定性，并比较了30和60秒的节奏。我们发现，在标称节奏林依晨就能约12S和34S精密测量在途时间，一个明星一样亮分别为55 CNC和K2-24。然后，我们进行了动力学仿真，其中还包括Ariel时间误差，我们发现通过TTV在类似K2-24的行星系统中对行星质量的测量约有20-30％的改进。我们还模拟了条件，允许我们使用Ariel的10条瞬态光曲线来检测假设的外部扰动在地球和海王星之间的质量范围内引起的TTV信号。