标题： 寻找中间状态者：TESS 行星系统有多拥挤？ 显示英文标题

标题： The Search for the Inbetweeners: How packed are TESS planetary systems?

摘要： 在这项工作中，我们研究了由凌日系外行星巡天卫星（TESS）发现的七个系统，以查看这些系统中是否有空间容纳一颗（或多颗）未被发现的行星潜伏在已确认的两颗行星之间。 在这五个系统中（即HD 15337；HD 21749；HD 63433；HD 73583和LTT 3780），我们发现有足够的空间让一颗未被发现的行星在已知行星之间运动。 换句话说，就目前的情况来看，这些系统并不是非常拥挤。 相比之下，已知TOI-1670两颗行星的摄动影响排除了它们之间存在额外行星的可能性。 最后一个系统TOI 421更具挑战性。 在大多数情况下，在已知行星轨道之间添加一颗地球质量的行星会导致系统不稳定。 我们对修改后的系统的绝大多数模拟在一百万年的尺度上都表现出动态不稳定性，仅约1.1%的模拟在这一时间尺度上是稳定的。 因此，似乎在TOI 421系统的两颗已知行星之间几乎没有空间容纳另一颗未被发现的行星存在，但仅凭动力学理由无法完全排除这种行星的存在。 显示英文摘要

摘要： In this work, we examine seven systems discovered by TESS, to see whether there is any room in those systems for an additional planet (or several) to lurk unseen between the two planets already confirmed therein. In five of those systems (namely HD 15337; HD 21749; HD 63433; HD 73583 and LTT 3780) we find that there is ample room for an undiscovered planet to move between those that have already been discovered. In other words, as they currently stand, those systems are not tightly packed. In stark contrast, the perturbative influence of the two known TOI-1670 planets is such that additional planets in between are ruled out. The final system, TOI 421, is more challenging. In the vast majority of cases, adding an Earth-mass planet to that system between the orbits of the known planets caused catastrophic instability. Just ~1.1% of our simulations of the modified system proved dynamically stable on a timescale of one million years. As a result, it seems that there is very little room between the two known planets in the TOI 421 system for an addition unseen world to exist, but the existence of such a planet can not be definitely ruled out on dynamical grounds alone.