Abstract

A common element in current theories of terrestrial planet formation is the prediction that the final stage in building terrestrial planets involves giant impacts between massive planetary embryos thousands of kilometres in diameter. Indeed a number of peculiarities about each of the terrestrial planets in our Solar system can be explained as a result of giant impacts like these, including the existence of our own Moon. In addition to forming terrestrial planets these giant impacts also produce copious amounts of debris, but thus far this debris has been poorly studied. We investigate debris production in the context of the Moon-forming collision, as the most well constrained example of a giant impact, and show that the debris forms a bright disk around the Sun that, around another nearby star, could be detectable for tens-of-millions of years by typical near infrared surveys. As such we expect systems undergoing terrestrial planet formation to possess detectable dust throughout the planet formation period and use this to analyse the frequency of terrestrial planet formation.