Cover Page
The handle
http://hdl.handle.net/1887/69725
holds various files of this Leiden University
dissertation.
Author: Bogelund, E.G.
A Molecular Journey
A Molecular Journey
Tales of sublimating ices from hot cores to comets
Proefschrift
ter verkrijging van
de graad van Doctor aan de Universiteit Leiden, op gezag van Rector Magnificus prof. mr. C.J.J.M. Stolker,
volgens besluit van het College voor Promoties te verdedigen op donderdag 14 maart 2019
klokke 10:00 uur
door
Eva Graulund Bøgelund
Promotores: Prof. dr. E.F. van Dishoeck Prof. dr. M.R. Hogerheijde Promotiecommissie: Prof. dr. H.J.A. R¨ottgering Prof. dr. A.G.G.M. Tielens
Prof. dr. P. Schilke (University of Cologne)
Prof. dr. I. de Pater (University of California, Berkeley) Dr. S. Charnley (Goddard Space Flight Center, NASA)
Cover design and layout by Wijnand Blok-Salinas Poblete Image credit: Adobe Stock (backgrounds)
ESO/S. Guisard, www.eso.org/∼sguisard (ALMA antennas)
“Vor Tid er Eventyrets Tid.”
Table of contents
1 Introduction 1
1.1 The formation of stars and planetary systems . . . 2
1.2 Chemistry in star-forming regions . . . 9
1.3 Star formation in the era of ALMA . . . 13
1.4 This thesis . . . 14
1.4.1 Analysis tools used in the thesis . . . 16
1.4.2 Overview of chapters and general conclusions . . . 17
1.5 A look to the future . . . 21
2 Low levels of methanol deuteration in the high-mass star-forming region NGC 6334I 25 2.1 Introduction . . . 27
2.2 Observations and analysis method . . . 30
2.2.1 Observations . . . 30 2.2.2 Analysis method . . . 30 2.3 Results . . . 34 2.3.1 13CH 3OH . . . 34 2.3.2 CH183 OH . . . 35 2.3.3 CH2DOH . . . 37 2.3.4 CH3OD . . . 39
2.4 Methanol deuteration fractions . . . 39
2.4.1 NGC 6334I . . . 39
2.4.2 Comparison with other sources . . . 45
2.4.3 Comparison with models . . . 47
2.5 Summary and conclusion . . . 49
Appendix . . . 52
3 Methylamine and other simple N-bearing species in the hot cores NGC 6334I MM1 – 3 77 3.1 Introduction . . . 79
3.1.1 Previous detections and potential formation routes for methy-lamine and related species . . . 79
3.1.2 NGC 6334 . . . 81
3.2 Observations and method . . . 81
3.2.1 Observations . . . 81
Table of contents
3.2.2 Method . . . 82
3.3 Results . . . 84
3.3.1 Methylamine CH3NH2 . . . 87
3.3.2 Summary of results on methanimine, methyl cyanide and formamide . . . 90
3.4 Discussion . . . 90
3.4.1 Methylamine towards NGC 6334I . . . 90
3.4.2 Methylamine towards other objects . . . 94
3.4.3 Comparison with comet 67P . . . 95
3.4.4 Other N-bearing species . . . 96
3.5 Summary . . . 96
Appendix . . . 98
4 Molecular complexity on disk-scales uncovered by ALMA: The chemical composition of the high-mass protostar AFGL 4176113 4.1 Introduction . . . 115
4.1.1 AFGL 4176 . . . 116
4.2 Observations and methods . . . 117
4.2.1 Observations . . . 117
4.2.2 Methods for line identification and modelling . . . 119
4.3 Results . . . 120
4.3.1 Upper limit on the column density of glycolaldehyde . . . . 122
4.3.2 Isotopologues with only blended lines . . . 123
4.3.3 Spatial distribution of selected species . . . 123
4.4 Discussion . . . 124
4.4.1 Comparison with the high-mass star-forming regions in Sgr B2(N) and Orion KL . . . 127
4.4.2 Comparison with the low-mass protobinary IRAS 16293–2422 . . . 130
4.4.3 Comparison with chemical models . . . 131
4.5 Summary . . . 133
Appendix . . . 134
5 Exploring the volatile composition of comets C/2012 F6 (Lem-mon) and C/2012 S1 (ISON) with ALMA 143 5.1 Introduction . . . 145
5.2 Observations . . . 146
5.3 Spatial distribution of molecules . . . 148
5.3.1 Comet Lemmon . . . 148
5.3.2 Comet ISON . . . 149
5.4 Model . . . 149
5.4.1 Molecular production rates and parent scale lengths . . . . 156
5.4.2 Formation scenarios for detected molecules . . . 158
5.4.3 Integrated intensity maps . . . 160
5.4.4 HCN(4–3)/(3–2) line ratio . . . 160
5.5 Conclusion . . . 163
