2435119

Target RA (J2000): 207.526169 and deg Target Dec (J2000): -40.83580 and deg Gaia GMag: 9.615 Programme ID: CH_PR240017 PI of observing programme: Chakraborty Title of programme: Accurate and precise characterisation of the HIP 67522 system in the presence of significant stellar variability Abstract: Young planets are excellent laboratories to test planet formation and evolution pathways. However the accurate characterisation of parameters like the radius of the planet is limited by the enhanced activity of the host star. The impact of features like unocculted and occulted active regions is a growing challenge in the era of high-precision photometry and transmission spectroscopy and better characterisation of these features is now more vital than ever for the correct interpretation of atmospheres on exoplanets. Here we propose to precisely characterise the HIP 67522 system a 17 Myr Solar-like star exhibiting significant stellar activity and one of the youngest planet-hosting stars discovered to date. The HIP 67522 system consists of one confirmed transiting hot Jupiter (planet b) and an unconfirmed outer planet candidate (planet c). To characterise this key young system we aim to: i) obtain an accurate and precise radius measurement for the known transiting planet (planet b) by quantifying the effect of stellar activity on its transit depth and ii) confirm the candidate exoplanet (planet c) by following up the most likely period aliases of its two known transits. While accurately measuring the radius of planet b is vital for testing different planet formation and evolution models for hot Jupiters confirming planet c will make this the youngest multi-planet transiting system ever discovered making this a very compelling system to be observed by CHEOPS. [truncated! Please see actual data for full text]

目标赤经（J2000）：207.526169 度，目标赤纬（J2000）：-40.83580 度，盖亚（Gaia）G星等：9.615，观测项目编号：CH_PR240017，观测项目首席研究员（Principal Investigator, PI）：查克拉博蒂（Chakraborty），项目标题：存在显著恒星活动的HIP 67522系统的高精度精确表征
摘要：年轻行星是检验行星形成与演化路径的绝佳实验室。然而，行星半径等参数的精确表征受宿主恒星增强的活动所限制。在高精度测光与透射光谱学时代，未掩食活动区与已掩食活动区等特征的影响是日益严峻的挑战，而对这些特征的更好表征，如今比以往任何时候都更为关键，以便正确解读系外行星大气。在此，我们提议对HIP 67522系统进行精准表征：该系统拥有一颗年龄为17 Myr的类太阳恒星，其展现出显著的恒星活动，是迄今发现的最年轻的拥有行星的恒星之一。HIP 67522系统包含一颗已确认的凌星热木星（行星b），以及一颗未确认的外侧系外行星候选体（行星c）。为表征这一关键年轻系统，我们的目标为：i）通过量化恒星活动对其凌星深度的影响，获取已知凌星行星（行星b）的高精度半径测量值；ii）通过追踪其两次已知凌星最可能的周期混叠信号，确认该系外行星候选体（行星c）。精准测量行星b的半径，对于检验热木星的不同行星形成与演化模型至关重要，而确认行星c将使该系统成为迄今发现的最年轻的多行星凌星系统，使其成为CHEOPS（系外行星特征卫星，Characterising Exoplanet Satellite）极具观测价值的目标。
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