标题： CHEOPS对HD 95338b的观测：精炼的凌星参数，以及寻找系外卫星 显示英文标题

标题： The CHEOPS view of HD 95338b: refined transit parameters, and a search for exomoons

摘要： 尽管已知的系外行星数量不断增加，但尚未有无可争议的系外卫星（称为系外月球）的检测结果。 寻找系外月球是系外行星科学的前沿课题。 某些空间仪器被认为适合这一目的。 我们展示了在这一领域中，CHaracterizing ExOPlanets Satellite（CHEOPS）在HD 95338行星系统中的进展。 我们提出了一种新方法，这是寻找系外月球的重要步骤。 我们利用地面光谱数据结合Gaia观测结果来获得精确的恒星参数。 这些参数随后被用作分析由CHEOPS和Transiting Exoplanet Survey Satellite（TESS）观测到的行星凌日的数据输入。 此外，我们主要通过四次CHEOPS观测的顺序方法，在偏心海王星大小的行星HD 95338b的希尔球区域内寻找卫星的迹象。 我们还简要探讨了该行星的凌日时间变化。 我们给出了改进的恒星和行星参数，将行星与恒星半径比的不确定性缩小了$10$倍。 我们还确定了HD 95338b的历表。 通过注入/检索测试，我们表明，使用这里提出的方法，可以在$5 \sigma$检测到系外月球，其置信度约为$R_{\rm Moon} = 0.8$~$R_\oplus$。 我们在$R_{\rm Moon} \approx 0.6$~$R_\oplus$的范围内排除了该系统中系外月球的凌日，在$1\sigma$置信度水平上。 用于寻找类似凌日事件的算法可以作为其他类似目标（由CHEOPS或其他任务观测）的基准。 显示英文摘要

摘要： Despite the ever-increasing number of known exoplanets, no uncontested detections have been made of their satellites, known as exomoons. The quest to find exomoons is at the forefront of exoplanetary sciences. Certain space-born instruments are thought to be suitable for this purpose. We show the progress made with the CHaracterizing ExOPlanets Satellite (CHEOPS) in this field using the HD 95338 planetary system. We present a novel methodology as an important step in the quest to find exomoons. We utilize ground-based spectroscopic data in combination with Gaia observations to obtain precise stellar parameters. These are then used as input in the analysis of the planetary transits observed by CHEOPS and the Transiting Exoplanet Survey Satellite (TESS). In addition, we search for the signs of satellites primarily in the form of additional transits in the Hill sphere of the eccentric Neptune-sized planet HD 95338b in a sequential approach based on four CHEOPS visits. We also briefly explore the transit timing variations of the planet. We present refined stellar and planetary parameters, narrowing down the uncertainty on the planet-to-star radius ratio by a factor of $10$. We also pin down the ephemeris of HD 95338b. Using injection/retrieval tests, we show that a $5 \sigma$ detection of an exomoon would be possible at $R_{\rm Moon} = 0.8$~$R_\oplus$ with the methodology presented here. We exclude the transit of an exomoon in the system with $R_{\rm Moon} \approx 0.6$~$R_\oplus$ at the $1\sigma$ level. The algorithm used for finding the transit-like event can be used as a baseline for other similar targets, observed by CHEOPS or other missions.