Formation and Evolution of Protoplanetary Discs

• Protoplanetary discs and the protostars they surround are formed from the gravitational collapse of molecularcloud cores. These discs consist primarily of gas, with a small but important dust component. The roughlymm-sized grains that make up the dust component are the building blocks of planets. Over a timescale of upto a few million years, the dust in protoplanetary discs is lost. Some of the dust will be locked up intoplanetesimals and planets, but the majority of the decrease in the dust mass is likely caused by the radial driftof pebbles.In this thesis, I have studied the evolution of protoplanetary discs, with a focus on the evolution of the dustdisc through the radial drift of pebbles. I developed a numerical model that includes the formation of the discfrom a collapsing molecular cloud core, viscous evolution and photoevaporation of the gas disc, as well as thegrowth 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 radialpebble drift using a population synthesis approach. We found that discs undergoing radial pebble drift cansustain sufficient dust masses for long enough to explain the observed decrease in dust masses in observedprotoplanetary discs.In Paper III, we conducted synthetic observations of discs, comparing how the total flux emitted fromprotoplanetary discs evolves with their apparent size. We examined how this relationship depends on theinitial angular momentum of the cloud core from which the discs are created and on the efficiency of viscousheating. We found that discs with high angular momentum and weak viscous heating provide the bestagreement with measurements of real discs. Additionally, we found that discs undergoing radial drift aregenerally optically thin.

Ämnesord

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Nyckelord

Protoplanetary discs

Accretion discs

planet formation

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