University of Groningen
The future of protoplanetary disk models
Greenwood, Aaron James
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Publication date: 2018
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Greenwood, A. J. (2018). The future of protoplanetary disk models: Brown dwarfs, mid-infrared molecular spectra, and dust evolution. Rijksuniversiteit Groningen.
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The future of protoplanetary
disk models
Brown dwarfs, mid-infrared molecular spectra, and dust evolution
Proefschrift
ter verkrijging van de graad van doctor aan de Rijksuniversiteit Groningen
op gezag van de
rector magnificus prof. dr. E. Sterken en volgens besluit van het College voor Promoties.
De openbare verdediging zal plaatsvinden op maandag 15 oktober om 12:45 uur
door
Aaron James Greenwood
geboren op 21 februari 1991 te Napier, Nieuw-Zeeland
Promotores
Prof. I.E.E. Kamp Prof. L.B.F.M. Waters
Beoordelingscommissie
Prof. F.F.S. van der Tak Prof. C. Dominik Prof. C. Helling
ISBN: 978-94-034-0820-0 (printed version) ISBN: 978-94-034-0819-4 (electronic version)
Cover:the MAGIC telescopes, Roque de los Muchachos Observatory, La Palma Inside back cover:New Zealand Tui “Tuition” by Joshua Drummond @tworuru Printed by GVO Drukkers & Vormgevers on recycled paper
C O N T E N T S
1 introduction 1
1.1 Goals of the thesis . . . 2
1.2 Disk formation . . . 3
1.3 Disk classification . . . 4
1.4 Disk observations . . . 6
1.5 Brown dwarfs and their disks . . . 9
1.6 Planets and brown dwarfs . . . 13
1.7 Dust structure, grain growth, and migration . . . 15
1.8 Modelling approaches . . . 17 1.9 Molecular spectroscopy . . . 18 1.10 Infrared spectra . . . 20 1.11 Disk models . . . 20 1.11.1 ProDiMo . . . 21 1.11.2 FLiTs . . . 23 1.11.3 Model results . . . 24 1.12 This thesis . . . 24
2 thermochemical modelling of brown dwarf disks 29 2.1 Introduction . . . 30
2.2 Models . . . 32
2.2.1 Defining the fiducial model . . . 33
2.2.2 12CO sub-mm lines from the fiducial model . . . 34
2.2.3 The fiducial model and grid selection . . . 38
2.2.4 Chemical modelling and comparisons with T Tauri disks . 40 2.3 Results and discussion . . . 43
2.3.1 Line ratios and flux predictions of brown dwarf disks . . . 44
2.3.2 Disk geometry . . . 46
2.3.3 HCN chemistry . . . 47
2.3.4 HCO+chemistry . . . 49
2.4 Conclusions . . . 53
vi contents
3 the infrared line-emitting regions of t tauri disks 55
3.1 Introduction . . . 56
3.2 FLiTs . . . 58
3.2.1 Computational requirements . . . 59
3.2.2 Data processing . . . 62
3.3 Disk models: a standard T Tauri model . . . 63
3.3.1 Line-emitting regions . . . 63
3.4 Permutations to the standard model . . . 67
3.4.1 Changes in the line-emitting area . . . 70
Sensitivity to gas and dust temperatures . . . 71
3.4.2 Spectra from the model series . . . 78
3.4.3 Absorption lines . . . 80
3.4.4 Dust settling . . . 81
3.5 Conclusions . . . 86
3.6 Acknowledgements . . . 87
3.7 Supplementary data . . . 87
4 the effects of dust evolution on disks in the mid-ir 107 4.1 Introduction . . . 108
4.2 Dust growth and migration . . . 110
4.3 Modelling strategy . . . 111
4.3.1 Model parameters . . . 112
4.4 Dust migration and disk surface densities . . . 113
4.5 Size of the dust disk . . . 115
4.6 Mid-infrared spectra . . . 121
4.6.1 Line fluxes: C2H2in comparison to other species . . . 125
4.6.2 Properties of the line-emitting regions . . . 125
4.7 Discussion . . . 132
4.8 Conclusion . . . 133
4.9 Acknowledgements . . . 134
5 conclusions and outlook 135
a english summary 141
b nederlandse samenvatting 155
acknowledgements 169
