Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596773
Title: The origin of hot dust around sun-like stars
Author: Booth, M.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2010
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Abstract:
Within our Solar System lie two belts of planetesimals, the asteroid belt and Kuiper belt. Collisions between these planetesimals produce the dust that forms our debris disc. Many other stars have been observed to be surrounded by debris discs much more massive than our own. Most of these discs can be explained by steady state collisional evolution. However, some systems have more hot dust present than we would expect given the age of the system. In this thesis we explore some potential explanations for this high level of hot dust. One potential explanation is that the dust is the result of a transient event similar to the Late Heavy Bombardment (LHB) in our own Solar System. We investigate the IR emission from the Kuiper belt during the history of the Solar System. We show that the Solar System would have been amongst the brightest debris discs before the LHB at both 24 and 70 μm. We find a significant increase in 24 μm emission during the LHB, which rapidly drops off and becomes undetectable within 30 Myr, whereas the 70 μm emission remains detectable until 360 Myr after the LHB. Comparison with the statistics of debris disc evolution shows that such depletion events must be rare occurring around less than 12% of Sun-like stars. The latest models for the formation of the asteroids suggest that large planetesimals could have formed quickly. We follow the collisional evolution of the early stages of the asteroid belt including dynamical depletion from embedded embryos and show what this would have looked like in terms of emission. Under these assumptions we find that the asteroid belt would be observable for ~100 Myr at 24 μm. We find that some systems showing an excess in 24 μm emission at young ages could be harbouring massive asteroid belts.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.596773  DOI: Not available
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