From the Centaurs to the Inner Oort Cloud: Exploring the Kuiper belt Connection

外太阳系的小天体是行星形成过程中遗留下来的物质，是太阳系历史的化石记录。这些星子可以大致分为半人马座、柯伊伯带和内奥尔特云。柯伊伯带由海王星外的轨道组成，轨道的距离大约在30-250 au之间。半人马是最近从柯伊伯带扩散出来的彗星的前身。这些天体是海王星和木星之间相对短暂的混沌轨道上的短暂人口，它们会穿过一颗或多颗巨行星。另一方面，内奥尔特云由与海王星动态激发和分离的轨道组成，半长轴大于~ 250 au，可能是由海王星以外的巨大行星或经过的恒星分散到它们的轨道上的。通过研究这些小冰态星子的系综性质（形状、大小、组成、轨道等物理特征），我们可以探索巨行星的早期动力学历史，探索太阳系原始星子盘的组成结构，并研究外太阳系随时间的演化。这些天体中的大多数都太微弱了，无法用地面望远镜进行光谱分析，但通过在不同的光学和近红外滤光器中测量宽带颜色，我们获得了一个小行星表面组成的代理。通过测量微行星随时间的亮度，我们可以估计其形状并测量其旋转速率。通过深度光学成像，我们可以寻找与类似彗星活动相关的微弱特征，并探索这些物体的水冰和其他挥发性物质的排气频率。这个项目的主要目的是探索半人马座、柯伊伯带和内奥尔特云之间的联系和演化历史。该项目将集中在两个主要途径来探索这些太阳系人口。第一种方法是利用1-8米望远镜和小行星地面撞击最后警报系统（ATLAS）的观测结果，研究柯伊伯带天体和半人马座样本的光曲线、相位曲线和彗星活动历史。第二条途径将包括用ATLAS调查来搜索遥远的奥尔特云内天体，以限制这一遥远天体群的大小和亮端星等分布。

The small bodies of the Outer Solar System are the material leftover from the construction of the planets and serve as a fossil record of the Solar System's history. These planetesimals can be broadly divided in the Centaurs, the Kuiper belt, and the Inner Oort cloud. The Kuiper belt consists of orbits beyond Neptune residing between approximately 30-250 au. Centaurs are cometary precursors that have recently diffused out of the Kuiper belt. These bodies are a transitory population on relatively short-lived chaotic orbits between Neptune and Jupiter that cross one or more of the giant-planets. The Inner Oort cloud on the other hand consists of dynamically excited and detached orbits from Neptune, with semimajor axes greater than ~ 250 au, likely scattered on to their orbits by a giant planet beyond Neptune or by a passing star. By studying the ensemble properties (shapes, sizes, compositions, orbits, and other physical characteristics) of these small icy planetesimals, we can probe the giant planets' early dynamical history, explore the compositional structure of the Solar System's primordial planetesimal disk, and study the evolution of the outer Solar System over time. The majority of these objects are too faint for spectroscopy with ground-based telescopes, but by measuring broad-band colors in different optical and near-infrared filters, we obtain a proxy for a planetesimal's surface composition. By measuring the brightness of a planetesimal over time, we can estimate shape and measure rotation rates. With deep optical imaging, we can look for faint features associated with comet-like activity and explore how often these objects experience outgassing of water ice and other volatile species.The main aim of this project is to explore the connection and evolutionary history of the Centaurs, Kuiper belt, and Inner Oort cloud. The project will focus on two main avenues for exploring these Solar System populations. The first will be through the study of light curves, phase curves, and the cometary activity histories of a sample of KBOs and Centaurs utilising observations from 1-8-m telescopes and the Asteroid Terrestrial-impact Last Alert System (ATLAS). The second avenue will consist of a search for distant inner Oort Cloud objects with the ATLAS survey in order to constrain the size and bright-end magnitude distribution of this distant population of bodies.