Promotor: Prof.dr. E.F. van Dishoeck

Multiple stars, that is two or more stars composing a gravitationally bound system, are common in the universe.

Low-mass main-sequence stars like our Sun are continuous sources of outflowing hot magnetised plasma. In the case of the Sun, this is known as the solar wind, whereas for other stars they are called stellar winds.

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

One of the key quests in astronomy is to study the growth and evolution of galaxies across cosmic time. Radio observations provide a powerful means of studying the formation of stars and subsequent buildup of distant galaxies, in a way that is unbiased by the presence of dust.

Wetenschappers bij de Leidse Sterrewacht onderzoeken de oorsprong van sterren en hun planetenstelsels. Ze detecteren en karakteriseren planeten rondom andere sterren (exoplaneten). Ze onderzoeken hoe sterren en planeten ontstaan. En ze volgen moleculen van interstellaire wolken tot planetenstelsels…

In this thesis chemical and physical processes in the ice mantles on interstellar dust grains are studied.

Promotor: Prof.dr. E.F. van Dishoeck, Prof.dr. F.F.S. van der Tak (RUG)

Galaxies form and evolve through close interaction with their surroundings. As a result, the heavy elements ('metals') that are synthesized in stars, are found both inside and outside galaxies.

This thesis investigates how galaxies form and what diversifies the evolutionary histories of galaxies.

The origin and evolution of galaxies are closely tied to the cyclic feedback processes between stars and the interstellar medium (ISM).

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. M. Franx, Prof.dr. P.G. van Dokkum (Yale University)

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

Promotor: Prof.dr. E. F. van Dishoeck

This thesis focus on the interaction between M dwarf stellar winds and Galactic cosmic rays and the possible effects on the habitability of exoplanets.

Sobral

Promotor: J. Schaye

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

OB associations are loose groups of young, massive stars. They constitute the last stage of the massive starformation process, and the context in which new stars are formed.

Promotores: Prof.dr. J. Schaye, Prof.dr. S.D.M. White (MPA Garching)

When observing star-forming galaxies, we are not only seeing stellar light, but we also see how this interacts with galactic gas and dust. This thesis contains studies of the stellar, nebular and dust properties of low mass star-forming galaxies.

Promotor: F.P. Israel, Co-Promoter: R. Meijerink

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.

Promotor: Prof.dr. M. Franx, Co-Promotor: Rychard Bouwens

The solar system was formed approximately 4.56 billion years ago. Despite the numerous theories that have been developed over the years, the formation and evolution of the solar system still remain unclear.

Promotor: P. T. de Zeeuw, Co-promotor: N. Neumayer; G. van de Ven

Op 25 september 2022 heeft in Leiden een bijzonder experiment plaatsgevonden: Seeing Stars Leiden. In de wijde omgeving van de Leidse Oude Sterrewacht gingen een uur lang alle lichten uit.

Promotor: Roeland M.H. Merks

Large areas of space are filled by molecular clouds that consist of gas and dust grains that are the remnants of dead stars. When these clouds start collapsing, the decreasing temperature and increasing density cause gas particles to start accreting onto dust grain surfaces.

This thesis develops a method for direction dependent calibration of the ionosphere in radio interferometric data.

Promotor: Prof.dr. E.F. van Dishoeck, Co-Promotor: G.J. Herczeg

Promotor: G.P. van Wezel

The high velocity tail of the total velocity distribution of stars provides essential insight into fundamental properties of the Galaxy.

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

Protein–protein complexes are formed via transient states called encounter complexes that greatly influence the formation of the stereospecific complex.

Promotores: Prof.dr. A.G.G.M. Tielens, Prof.dr. L. Kaper (UvA)

This thesis aims to enhance our understanding of galaxies by testing theoretical models of galaxy formation against observations, particularly in the cases of extreme systems which have been found to have an excess of baryonic mass in their central regions, in the form of either supermassive black holes…

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

Stars like the sun are born in large molecular clouds existing from gas and dust. During the formation process, the chemical composition of the material can be altered drastically by the changing physical conditions.

Promotor: Prof.dr. H.V.J. Linnartz

The formation and evolution of galaxies is fundamentally driven by the formation of new stars out of cold gas.

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

Promotor: M. Franx, Co-Promotor: I.F. Labbé

We investigate the buildup of galaxies from various vantage points. The first two chapters focus on the stellar content of galaxies, especially the distribution of stellar masses at birth and potential variations therein in various galactic environments.

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