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Formation and Evolution of Protoplanetary Discs

Appelgren, Johan LU (2024)
Abstract
Protoplanetary discs and the protostars they surround are formed from the gravitational collapse of molecular
cloud cores. These discs consist primarily of gas, with a small but important dust component. The roughly
mm-sized grains that make up the dust component are the building blocks of planets. Over a timescale of up
to a few million years, the dust in protoplanetary discs is lost. Some of the dust will be locked up into
planetesimals and planets, but the majority of the decrease in the dust mass is likely caused by the radial drift
of pebbles.
In this thesis, I have studied the evolution of protoplanetary discs, with a focus on the evolution of the dust
disc through the radial drift of pebbles. I developed... (More)
Protoplanetary discs and the protostars they surround are formed from the gravitational collapse of molecular
cloud cores. These discs consist primarily of gas, with a small but important dust component. The roughly
mm-sized grains that make up the dust component are the building blocks of planets. Over a timescale of up
to a few million years, the dust in protoplanetary discs is lost. Some of the dust will be locked up into
planetesimals and planets, but the majority of the decrease in the dust mass is likely caused by the radial drift
of pebbles.
In this thesis, I have studied the evolution of protoplanetary discs, with a focus on the evolution of the dust
disc through the radial drift of pebbles. I developed a numerical model that includes the formation of the disc
from a collapsing molecular cloud core, viscous evolution and photoevaporation of the gas disc, as well as the
growth and radial drift of the dust disc.
In Papers I and II, we explored the temporal evolution of the dust mass in protoplanetary discs due to radial
pebble drift using a population synthesis approach. We found that discs undergoing radial pebble drift can
sustain sufficient dust masses for long enough to explain the observed decrease in dust masses in observed
protoplanetary discs.
In Paper III, we conducted synthetic observations of discs, comparing how the total flux emitted from
protoplanetary discs evolves with their apparent size. We examined how this relationship depends on the
initial angular momentum of the cloud core from which the discs are created and on the efficiency of viscous
heating. We found that discs with high angular momentum and weak viscous heating provide the best
agreement with measurements of real discs. Additionally, we found that discs undergoing radial drift are
generally optically thin. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Doctor Pinilla, Paola, University College London
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Protoplanetary discs, Accretion discs, planet formation
pages
119 pages
publisher
Lund University
defense location
Lundmarksalen, Sölvegatan 27, Lund
defense date
2024-03-14 09:00:00
ISBN
978-91-8039-898-5
978-91-8039-899-2
project
Planet formation around young stars
language
English
LU publication?
yes
id
186b722a-11f5-4ade-8ed2-28aa4e945995
date added to LUP
2024-02-12 10:54:46
date last changed
2024-02-16 09:34:34
@phdthesis{186b722a-11f5-4ade-8ed2-28aa4e945995,
  abstract     = {{Protoplanetary discs and the protostars they surround are formed from the gravitational collapse of molecular<br/>cloud cores. These discs consist primarily of gas, with a small but important dust component. The roughly<br/>mm-sized grains that make up the dust component are the building blocks of planets. Over a timescale of up<br/>to a few million years, the dust in protoplanetary discs is lost. Some of the dust will be locked up into<br/>planetesimals and planets, but the majority of the decrease in the dust mass is likely caused by the radial drift<br/>of pebbles.<br/>In this thesis, I have studied the evolution of protoplanetary discs, with a focus on the evolution of the dust<br/>disc through the radial drift of pebbles. I developed a numerical model that includes the formation of the disc<br/>from a collapsing molecular cloud core, viscous evolution and photoevaporation of the gas disc, as well as the<br/>growth and radial drift of the dust disc.<br/>In Papers I and II, we explored the temporal evolution of the dust mass in protoplanetary discs due to radial<br/>pebble drift using a population synthesis approach. We found that discs undergoing radial pebble drift can<br/>sustain sufficient dust masses for long enough to explain the observed decrease in dust masses in observed<br/>protoplanetary discs.<br/>In Paper III, we conducted synthetic observations of discs, comparing how the total flux emitted from<br/>protoplanetary discs evolves with their apparent size. We examined how this relationship depends on the<br/>initial angular momentum of the cloud core from which the discs are created and on the efficiency of viscous<br/>heating. We found that discs with high angular momentum and weak viscous heating provide the best<br/>agreement with measurements of real discs. Additionally, we found that discs undergoing radial drift are<br/>generally optically thin.}},
  author       = {{Appelgren, Johan}},
  isbn         = {{978-91-8039-898-5}},
  keywords     = {{Protoplanetary discs; Accretion discs; planet formation}},
  language     = {{eng}},
  month        = {{02}},
  publisher    = {{Lund University}},
  school       = {{Lund University}},
  title        = {{Formation and Evolution of Protoplanetary Discs}},
  url          = {{https://lup.lub.lu.se/search/files/171169048/Johan_Appelgren_WEBB.pdf}},
  year         = {{2024}},
}