Cover Page
The handle
https://hdl.handle.net/1887/3158796
holds various files of this Leiden
University dissertation.
Author: Concha Ramirez, F.A.
Title: Simulating the birth environment of circumstellar discs
Issue Date: 2021-04-06
Simulating the birth environment
of circumstellar discs
Simulating the birth environment of
circumstellar discs
Proefschrift
ter verkrijging van
de graad van doctor aan de Universiteit Leiden, op gezag van rector magnificus prof. dr. ir. H. Bijl,
volgens besluit van het college voor promoties te verdedigen op 6 april 2021
klokke 15.00 uur
door
Francisca Andrea Concha Ramírez
geboren te Temuco, Chile in 1988
Promotiecommissie
Promotor: Prof. dr. S.F. Portegies Zwart Co-promotor: Dr. M.R. Hogerheijde
Overige leden: Prof.dr. H.J.A. Röttgering University of Leiden Prof.dr. J.S. Kaastra University of Leiden Prof.dr. C.W.M. Fridlund University of Leiden Dr. E. Sellentin University of Leiden Prof.dr. C. Dominik University of Amsterdam Dr. E. Kokubo University of Tokyo Prof.dr. S. Pfalzner Forschungszentrum Jülich
Cover design by Francisca Concha-Ramírez.
The background colour of the cover is Cosmic Latte [#FFF8E7, RGB (255, 248, 231)], the average colour of the Universe (Baldry et al. 2002). This colour is obtained by averaging the light emitted by 20,000 galaxies from the 2dF Survey (Colless et al. 2001).
There is no thing as a single-issue struggle because we do not live single-issue lives.
1. Introduction 1
1.1. Star clusters . . . 3
1.1.1. Formation and evolution . . . 3
1.1.2. Evolutionary time scales and radii . . . 6
1.2. Circumstellar discs . . . 7
1.2.1. Formation and evolution . . . 8
1.2.2. Disc masses and sizes . . . 10
1.3. Effects of the environment on circumstellar disc evolution . . . 11
1.3.1. Dynamical truncations . . . 12
1.3.2. External photoevaporation . . . 13
1.3.3. Ram pressure stripping . . . 16
1.3.4. Supernovae . . . 17 1.4. Numerical simulations . . . 18 1.4.1. N-body codes . . . 18 1.4.2. Smoothed-particle hydrodynamics . . . 19 1.4.3. AMUSE . . . 19 1.5. This thesis . . . 20
2. Viscous evolution of circumstellar discs in young star clusters 25 2.1. Introduction . . . 26
2.2. Methods . . . 27
2.2.1. Evolution of isolated viscous discs . . . 27
2.2.2. Gas in the cluster . . . 29
2.2.3. Dynamical disc truncation . . . 30
2.2.4. Numerical implementation . . . 30
2.3. Results . . . 31
2.3.1. Initial conditions . . . 31
2.3.2. The effect of gas in the cluster . . . 33
2.3.3. Evolution of the circumstellar discs . . . 33
2.3.4. Comparison with observations . . . 34
2.4. Discussion . . . 38
2.5. Summary and conclusions . . . 41
3. External photoevaporation constrains time-scale for planet formation 43 3.1. Introduction . . . 44
3.2. Model . . . 46
3.2.1. Viscous growth of circumstellar discs . . . 46
3.2.2. Dynamical truncations . . . 47
3.2.3. External photoevaporation . . . 47
3.2.4. Initial conditions . . . 51
3.3. Results . . . 54
3.3.1. Disc mass loss in time . . . 54
3.3.2. Disc lifetimes . . . 57
3.4. Discussion . . . 60
3.4.1. Disc survival and consequences for planet formation . . . 60
3.4.2. Influence of initial conditions . . . 61
3.4.3. Model caveats . . . 62
3.5. Conclusions . . . 64
3.A. Resolution of the discs . . . 64 vii
4. Effects of stellar density on photoevaporation of circumstellar discs 67
4.1. Introduction . . . 68
4.2. Model . . . 69
4.2.1. Stars and circumstellar discs . . . 70
4.2.2. External photoevaporation . . . 70
4.2.3. Initial conditions . . . 71
4.2.4. Model caveats . . . 72
4.3. Results . . . 73
4.3.1. Disc fractions and lifetimes . . . 75
4.3.2. Disc masses . . . 77
4.4. Discussion . . . 80
4.5. Conclusions . . . 80
5. Evolution of circumstellar discs in young star-forming regions 83 5.1. Introduction . . . 84
5.2. Model . . . 86
5.2.1. Molecular cloud collapse and star formation . . . 86
5.2.2. Stellar dynamics and circumstellar discs . . . 87
5.2.3. Initial conditions . . . 91
5.3. Results . . . 91
5.3.1. Star formation and cluster evolution . . . 91
5.3.2. Disc masses . . . 96
5.4. Discussion . . . 100
5.5. Summary and conclusions . . . 103
Bibliography . . . 106 Bibliography 107 English summary 123 Nederlandse samenvatting 127 Resumen en español 131 List of publications 135 Curriculum Vitae 137 Acknowledgements 139
