This thesis focuses on protoplanetary disks: flattened structures of gas and dust around young stars in which planets are expected to form and grow.

Promotores: Prof.dr. A.G.G.M. Tielens, Prof.dr. L.B.F.M. Waters (UvA), Prof.dr. C. Dominik (UvA)

My work focuses on a class of astronomical objects called protoplanetary disks.

The work presented in this thesis is based on ALMA surveys of protoplanetary disks in three star-forming regions: Lupus, OMC-2, and NGC 2024.

To study how planetary systems come into existence we study much younger systems still in formation.

Counter-Discourse in Zimbabwean Literature is a study of specific aspects of counter-discursive Zimbabwean narratives in English. In discussing the selected texts, my thesis is based on Terdiman’s (1989) the postcolonial concept of counter-discourse.

This thesis examines the link between simple molecules and the underlying structure and chemistry within protoplanetary disks - the birthplaces of planets.

A large diversity of exoplanetary systems has been found, but it is still unclear what drives this diversity.

Promotor: C.U. Keller, Co-Promotor: F. Snik

What is the origin of solar systems?

In the discs of dust and gasses around young stars, mysterious structures occur. Together with professor Ewine van Dishoeck, PhD student Paolo Cazzoletti investigate how we can explain these forms, such as rings, spirals and holes. On 12 December, he will defend his thesis.

Promotor: E. F. van Dishoeck, Co-promotor: C. Walsh

Planets are formed in disks of gas and dust around young stars.

Detecting planets during their formation stages is crucial for understanding the history and diversity of fully developed planetary systems like our own. However, observing young planets directly is challenging because they are often deeply embedded within their host protoplanetary discs, rich in gas…

Research using the ALMA telescope by scientists including Leiden's John Tobin and Steven Bos has produced the first images of the water snow line within a protoplanetary disc. Publication in Nature on 14 July.

To address the fundamental questions of how life on Earth emerged and how common life may be in the Universe, it is crucial to know the chemical composition of the planet-forming material.

Promotores: Prof.dr. E.F. van Dishoeck, Prof.dr. C.P. Dullemond

This thesis discusses the physical and chemical processes than influence the composition of forming planets.

The formation of stars and planets happens over multiple scales, which can interact. In particular, planet formation happens in the dense, complex environment of star forming regions.

This thesis focusses on the temperature structure in protoplanetary disks. The relation between structures seen in the dust and gas-phase molecules is investigated.

This thesis takes steps toward understanding the interaction between gas-phase and solid-state molecules in star- and planet-forming regions.

High-angular-resolution observations of the circumstellar material have uncovered numerous and very diverse substructures in protoplanetary discs, raising the question of whether they are caused by forming planets or other mechanisms.

The focus of this thesis is how stars like our Sun and planets like Jupiter, Saturn, and Earth are formed.

We have conducted a full spectral line survey of the 3-13 micron region of two massive protostars, AFGL 2591 and AFGL 2136, for the first time at high spectral resolution.

Circumstellar discs are the reservoirs of gas and dust that surround young stars and have the potential to become planetary systems.

Planet formation is a surprisingly homogeneous process that does not take place gradually from inside out, but that occurs everywhere at the same time in a proto-planetary disc, as Dave Lommen has discovered. He will obtain his doctorate this week based on his research into the dust around young stars…

Walsh

All comets might share their place of birth, new research says. For the first time ever, astronomer Christian Eistrup applied chemical models to fourteen well-known comets, surprisingly finding a clear pattern. His publication has been accepted in the journal Astronomy & Astrophysics.

Astronomer Jos de Boer has received the Chesneau Prize in Nice for his research into so-called protoplanetary disks. The prize is awarded to the best astronomical dissertation in the field of high angular resolution. 'I consider it a good opportunity to talk about my research.'

A team of scientists, including Leiden Astronomer Alice Booth, has discovered silicon monosulfide molecules in the dust disk around a young star. Such molecules indicate planet formation. The team made the discovery using the ALMA telescopes. This method provides an alternative when direct observation…

PhD defence

These are the proposed research projects for LEAPS 2019. Please note that not all projects will go ahead and some may still be added in the near future. Final funding decisions lie with the Faculty sponsors. And please make a note that if you are interested in an ESA project, to check if your state…

Dit rapport maakt deel uit van het project Receptenboek burgerparticipatie in opdracht van de Rijksdienst voor het Cultureel Erfgoed (RCE) en met steun van het Fonds voor Cultuurparticipatie.

Promotor: Prof.dr. E.F. van Dishoeck, Co-Promotor: M.R. Hogerheijde

A team of European astronomers under Leiden leadership has discovered that dust particles around a star already coagulate before the star is fully grown. These agglomerated dust particles are the first step in the formation of planets. The research publish their discovery in the journal of Nature As…

This thesis describes the development and validation of new high-contrast imaging techniques, with the ultimate goal of enabling the next generation of instruments for ELT-class telescopes to directly image Earth-like extra-solar planets orbiting around nearby stars.

An international team of astronomers including Leiden scientists publishes the image of a young star with a surrounding dust disk that is still being fed from its surroundings. The phenomenon around the star SU Aur may explain why so many exoplanets are not neatly aligned with their star. The European…

Could water be present in planet-forming disks before the formation of rocky planets? The James Webb Space Telescope may have found evidence for that. Webb has for the first time observed water in the inner disc around young star where at greater distance, giant planets have already formed. The research…

With 8.9 million euros from the Danish National Research Foundation, Aarhus University and Leiden Observatory will establish the Center for Interstellar Catalysis. The centre is led by Aarhus professor Liv Hornekær and aims to find out how and when the building blocks of life formed in the Universe.…

While investigating 16 years of images of young stars from a retired astronomical camera, Leiden master's student Sam de Regt discovered that two of those stars were still enveloped in birth clouds. Never before has anyone captured these two stars in so much detail. He publishes his data-cleaning method…

All the planets in our solar system orbit around the Sun in an ecliptical plane. This is to be expected because our solar system was formed from a so-called protoplanetary disc. PhD candidate Anna Miotello has studied these kinds of discs and how they influence the formation of stars and planets. PhD…

An international team of scientists, including Xander Tielens of Leiden Observatory, has used space telescope Hubble and the ALMA observatory to show that UV radiation from massive stars can prevent planets from forming. The researchers publish their findings on 1 March in the journal Science.

For the first time, astronomers have detected the presence of complex organic molecules, the building blocks of life, in a protoplanetary disc surrounding a young star. The discovery reaffirms that the conditions that spawned the Earth and Sun are not unique in the Universe. The results are published…

This programme aims to identify the intellectual contexts that were of importance for the architectural theory of the period, and especially to clarify the relation of architectural theory to primitivism.

How do molecules originate and evolve in space? And how does that ultimately determine the chemical composition of planets and their atmospheres? The Dutch Astrochemistry Network (DANIII) receives 1.6 million euros from NWO to find out. A large group of Leiden astronomers and chemists is contributing:…

Tradition has it that at the end of each academic year, the best master’s thesis in Political Science is awarded a prize. For 2021-2022, the jury is considering six nominations. All of great quality, but on different topics. These range from political party bans to questions regarding commitment within…

An unprecedented space telescope, an astrolab that makes space ice and molecules that may lead to the origin of life… The Ice Age project has all the prerequisites to become a very fascinating research project – if it is not one already. Leiden astronomers Melissa McClure, Harold Linnartz and Will Rocha…

From time to time, manuscripts that have remained hidden for centuries turn up in library collections and archives. In the archives of the 17th-century Bibliotheca Thysiana at the Rapenburg in Leiden, kept in the Leiden University Library, Rotterdam researcher Erik-Jan Bos discovered a hitherto unknown…

The Caribbean as we know it today is fundamentally a product of colonial activity and globalisation. Practically everyone that inhabits the Caribbean has ancestors from different continents due to colonial activity, which profoundly affects the area to this day. Caribbean writers, both in the Caribbean…