Infrared light on the composition of the dust surrounding carbon-rich stars

Abstract

Alle rechten voorbehouden. Niets uit deze uitgave mag worden verveelvoudigd, opgeslagen in een geautomatiseerd gegevensbestand, of openbaar gemaakt, in enige vorm of op enige wijze, hetzij elektronisch, mechanisch, door fotokopieën, opnamen of enige andere manier, zonder voorafgaande schriftelijke toestemming van de uitgever. PrefaceMy first contact with astrophysics was during the introductory astronomy lectures taught by Ed van den Heuvel. From this very first moment I have been captured by a certain charm present throughout astrophysics. Of course the beauty of simplicity, to reduce any given system to its essentials, can be found in astrophysics and physics alike. However, the charm of astrophysics lies also in a totally different beauty. The beauty to do things in a clumsy, impractical way. For astronomy is a science with a history. In every corner of astronomy you find tantalising relics: habits, methods and units inherited from the past. They range from 'O Be A Fine Girl, Kiss Me' to plotting-axes that run the "wrong" way . Of course such silly details sometimes make me want to bang my head on the table, especially when converting ergs/cm 2 /s/Å/sr to Jansky again and taking again more than three tries to get it right. But still, the fact that we have to use the observations from 1987 to study supernova 1987a, gives another dimension to the field.On top of these charms, the study of the stars never fails to trigger a slight surprise in me. The same surprise that you will hear in the voice of non-astronomers: "How can we learn so much about the stars, when they are so far away and all you get is a little bit of light?".After finishing undergraduate astronomy it was very clear to me that I was trained for doing research. I am happy that Rens Waters and Xander Tielens asked me to do a research project under their supervision. That research has resulted in this thesis. I have certainly received a lot of support while doing my research and this is the place where I would like to express my gratitude.First of all, I want to thank Xander and Rens for allowing me the independence I need to work well. Rens; your enthusiasm has often kept me going when I; after weeks of staring; could not find anything interesting anymore in the things that I was doing. Xander, I have enjoyed your practical approach and your encyclopedic knowledge of solid-state physics and literature. I will never forget that time when you took a paper with a only few references scribbled on it from your notebook and handed it to me. You didn't remember what references these were but you said: "Maybe they are of some use." and they were.Words of thanks to Caroline and Els for the very fruitful collaborations that we have had. We started our PhD projects around the same time and I have learned much from observing the way you both handled things. I have always appreciated the support and the gentle way in which you could criticise me: "Maybe have another look at this?". Ciska, you also started your PhD project together with me and we shared office...