Origin of Planets (C1)

2. Origin of Planets (C1)#

In these 12 lectures we are going to look at how planets form. Our search for life is centred on planets, as these provide the only known environments life is likely to form in: planets host the pressures, temperatures, and chemical conditions required for life as we understand it to emerge and survive. An appreciation of why, how, and what planets form in the universe is thus a key first step in our search for habitable and inhabited environments.

As we now know, planet formation is a very common occurrence. Most, if not all, stars host planetary objects around them. However, for a long time the only direct evidence we had for planets forming around stars was our own solar system. This left us to wonder from a theoretical perspective whether planet formation was likely at all, and whether planets and planetary architectures like our solar system’s were the inevitable outcome.

Here, we will consider the properties of the universe that allow planet formation to occur, the processes that synthesize elements planets are built out of, how those elements assemble into vast cosmic structures that progressively condense into stars and planets, how planets grow from this material, and how the debris left over modifies the final chemical and physical state of planets. In this, we learn about the planetary population we have discovered to date, and the methods we have used to identify them. With this knowledge, we are able to place the solar system in its galactic context.

Learning outcomes

The overarching learning outcomes for this module are below, lecture-specific learning outcomes are included in the notes for each lecture.

  • Where the material for planets comes from.

  • How planet forming material produces planetary systems.

  • The modes of planetary accretion.

  • The structure of planets.

  • The architectures of planetary systems.

  • How we observe planetary systems.

  • The role of planet forming debris in early planet evolution.

Lectures