The small bodies of our and other planetary systems

提出的研究计划旨在了解驱动行星系统从初始状态到现在状态的过程。这项研究将通过行星系统中较小的天体——矮行星、小行星、彗星和流星体——即亚行星体（简称spb）的透镜进行。在我们自己的太阳系中，spb数量丰富，分布广泛，大小和组成多种多样。我们银河系中的大多数恒星也有行星系统，其中许多已知也含有spb。因此，从行星系统到银河系本身，spb都是丰富的信息来源。***这个研究问题将通过三个主要主题来解决：1)在我们的太阳系中建立当前的亚行星体储存库；2)利用流星作为低成本的“样本返回任务”来了解它们在太空中的父母；3)利用我们对太阳系的了解来探索系外行星系统。亚行星天体在科学上很重要。它们是地球和其他行星（包括我们的系统和系外行星系统）形成的成分，因此它们是行星诞生时代的“化石”。2) spb在行星系统内的当前位置是该系统内大规模变化的示踪剂。例如，行星围绕恒星运行的距离比现在更近还是更远？3) spb与恒星同时形成，为了解恒星诞生过程提供了重要的线索。***在更广泛的背景下，spb对地球上的生命及其环境的研究很重要，因为1)它们向我们的星球提供了水和碳基有机分子，2)spb通过大型小行星撞击和灭绝事件塑造了地球上的生命。****SPBs也与整个社会相关。1)流星雨很容易接近，并使公众参与科学。2)最亮的流星事件（“火球”），比如2013年2月在俄罗斯车里雅宾斯克上空发生的事件，构成了一种尚未完全理解的公共危险。车里雅宾斯克事件在到达之前没有被发现，它释放的能量是广岛原子弹在大城市上空的30倍。爆炸造成的建筑物损失达3300万美元，1500人被送往医院接受治疗。3)最大的小行星对我们整个星球构成了一个小而不可忽视的威胁，并在最高政治层面上产生了反应。例如，在1994年和2005年，美国国会特别授权美国宇航局寻找危险的近地小行星，并分析使其偏转的选择，这已经被报道过，例如，纽约时报（“美国宇航局面临资金短缺寻找杀手小行星”，2007年3月12日）和彭博社（“小行星可能杀死我们所有人”）。国会正在精打细算（2017年5月11日）。由于所有这些原因，spb在科学上是有趣的，对加拿大人和全球社会都是相关的

The proposed research program is directed at understanding the processes that drive a planetary system from its initial to its present state. This research is to be conducted through the lens of a planetary system's smaller bodies -- dwarf planets, asteroids, comets and meteoroids – sub-planetary bodies or SPBs for short. SPBs are abundant, widespread and diverse in size and composition in our own solar system. Most stars in our galaxy also have planetary systems and many are known to contain SPBs as well. As a result, SPBs are rich sources of information at scales from planetary systems up to the Galaxy itself.***This research problem will be addressed through three major themes: I) establishing the current reservoirs of sub-planetary bodies in our solar system II) using meteors as low-cost 'sample-return missions' to learn about to their parents in space, and III) using our understanding of the Solar System to explore exoplanetary systems.***Sub-planetary bodies are important scientifically. 1) They are the ingredients from which Earth and other planets (both in our system and exoplanetary systems) formed, and so they are 'fossils' from the era of planet birth. 2) SPBs current locations within a planetary system are tracers of large-scale changes within it. For example, did the planets perhaps orbit their star closer to or farther away than they do now? 3) SPBs formed at the same time as their star, providing important insight into the process of star birth.***In a broader context, SPBs are important to the study of life on Earth and its environment because 1) they delivered both water and carbon-based organic molecules to our planet, 2) SPBs have shaped life on Earth through large asteroid impacts and extinction events.****SPBs are also relevant to society at large. 1) Meteor showers are easily accessible and engage the general public in science. 2) The brightest meteor events ('fireballs'), such as the one over the Russian city of Chelyabinsk in February 2013, constitute an incompletely understood public danger. The Chelyabinsk event was undetected prior to its arrival and released 30 times the energy of the Hiroshima bomb over a major city. The resulting explosion caused $33 million USD damage to buildings, and sent 1500 people for medical treatment. 3) The largest asteroids pose a small but non-negligible threat to our entire planet and have generated responses at the highest political level. For example, in 1994 and again in 2005, US Congress specifically mandated NASA find hazardous near-Earth asteroids and analyze options for deflecting them, This has been reported on by, for example, the NY Times ('NASA faces funding crunch to find killer asteroids', March 12 2007) and Bloomberg ('An Asteroid May Kill Us All. Congress Is Pinching Pennies', May 11 2017). For all these reasons, SPBs are both scientifically interesting and of relevance to Canadians and to the global community.**