K2-OjOS项目：K2活动5、16和18中的新行星和候选行星
The K2-OjOS Project: New and revisited planets and candidates in K2 campaigns 5, 16, & 18
摘要：
K2-OjOS是专业和业余天文学家之间的合作项目，主要旨在探测，表征和验证新的太阳系外行星。在这项工作中，10名业余天文学家通过目视检查K2 campaign 18（C18）的20 427条光变曲线来寻找行星信号。他们发现了42颗行星候选者，其中18颗是新发现的，24颗是以前在重叠的C5中发现的。我们使用了档案测光和光谱观测，以及新的高空间分辨率图像，以便对发现的候选者进行全面分析，包括宿主恒星的均匀特性，凌日建模，寻找凌日时间变化和统计验证。因此，我们报告了4颗新行星（K2-355 b，K2-356 b，K2-357 b和K2-358 b）和14颗候选行星。此外，我们通过对C5，C16（可用时）和C18光度数据进行建模，改进了先前公布的行星和候选者的凌日星历，大大提高了周期和中期凌日时间的精度。关于单个系统，我们强调了新的行星K2-356 b和候选EPIC 211537087.02接近2：1的周期性，在明亮的恒星K2-184（V = 10.35）中检测到重要的TTV，根据乐观模型，K2-103 b在宜居带内的位置，在已知系统K2-274中检测到新的单凌日，以及K2-120 b的处置重新分配，我们认为这是一颗行星候选人，因为信号的起源无法确定。
英文摘要：
We present the first results of K2-OjOS, a collaborative project between professional and amateur astronomers primarily aimed to detect, characterize, and validate new extrasolar planets. For this work, 10 amateur astronomers looked for planetary signals by visually inspecting the 20 427 light curves of K2 campaign 18 (C18). They found 42 planet candidates, of which 18 are new detections and 24 had been detected in the overlapping C5 by previous works. We used archival photometric and spectroscopic observations, as well as new high-spatial resolution images in order to carry out a complete analysis of the candidates found, including a homogeneous characterization of the host stars, transit modelling, search for transit timing variations and statistical validation. As a result, we report four new planets (K2-355 b, K2-356 b, K2-357 b, and K2-358 b) and 14 planet candidates. Besides, we refine the transit ephemeris of the previously published planets and candidates by modelling C5, C16 (when available) and C18 photometric data jointly, largely improving the period and mid-transit time precision. Regarding individual systems, we highlight the new planet K2-356 b and candidate EPIC 211537087.02 being near a 2:1 period commensurability, the detection of significant TTVs in the bright star K2-184 (V = 10.35), the location of K2-103 b inside the habitable zone according to optimistic models, the detection of a new single transit in the known system K2-274, and the disposition reassignment of K2-120 b, which we consider as a planet candidate as the origin of the signal cannot be ascertained.
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。
