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…

Diverse types of exoplanets such as gas giants on close-in orbits (hot Jupiters) and young massive giants on wide orbits (super Jupiters), with no analogs in the Solar System, pose challenges but also opportunities to our understanding of planet formation and evolution.

This thesis addresses the chemical processes that determine the compositions of giant planet atmospheres.

One of the key discoveries in exoplanet research over the past decade is the abundance of small planets in our Milky Way. Despite their high numbers, our understanding of their atmospheres remains limited, and it is unknown if they possess atmospheres at all.

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…

Even though more than 4000 extra-solar planets are known today, only a small fraction of these has been captured in an image. To better understand the planet formation mechanisms in solar-like environments we started the Young Suns Exoplanet Survey (YSES).

Over the last three decades, the discovery of exoplanets has revealed the boundless variety of worlds beyond our own Solar System⁠. Majority of planetary systems contain short-period planets that are larger than Earth but smaller than Neptune⁠.

A remarkable population of short period transiting rocky exoplanets with equilibrium temperatures on the order of 2,000 K has recently been discovered.

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

Over the past years it has been discovered that the population of extra-solar planets is large and diverse.

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

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.

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

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

Until the 1990s, the only known planets were those in our Solar System. Three decades later, several thousand exoplanets have been discovered orbiting stars other than the Sun, and substantial efforts have been made to explore these strange new worlds through spectroscopic analyses of their atmosphe…

Promotor: Christoph U. Keller, Co-promotores: Matthew A. Kenworthy, Frans Snik

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

This research focuses on the distribution of chemical elements in protoplanetary disks, the birthplaces of planets. These disks form around young stars and contain gas and dust, from which planets grow. Ice plays a crucial role in planet formation, aiding the clumping of dust particles and influencing…

More than 5,000 exoplanets have been found over the past couple of decades. These exoplanets show a tremendous diversity, ranging from scorching hot Jupiters, common super-Earths, to widely separated super-Jupiters on the planet/brown dwarf boundary.

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

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

Promotor: I. Snellen, Co-Promotor: M. Kenworthy

The thesis addresses the long-term dynamical evolution of hierarchical multiple systems.

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

Hot rocky exoplanets are planets that orbit so close to their host star that they possess a molten surface.

This thesis is an experimental study of the UV irradiation of the interstellar ice analogues, relevant for the different stages of the star and planet formation sequence.

When a star is born in our Galaxy, it is quite likely that it has formed within a massive cluster, which hosts numerous high-mass stars bathing their lower mass neighbours in UV radiation.

Promotor: Prof.dr. A.G.G.M. Tielens, Prof.dr. C. Dominik (UvA)

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

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

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.

Astronomical observations of cold regions in the universe show a rich inventory of ices. Part of these ices may end up on planets like our own, but in that journey they will be exposed to considerable amounts of radiation.

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.

Promotor: H.V.J. Linnartz

This thesis describes the Multi-site All-Sky CAmeRA (MASCARA), which consists of two small robotic telescope designed to detect exoplanets around the brightest stars in the sky.

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

Op deze pagina vindt u de opnames van de online This Week's Discoveries vanaf 12 mei 2020 en een lijst sprekers vanaf oktober 2015.

This thesis aims to demonstrate how the achromatic nature and design flexibility of liquid-crystal optics can be used to improve high-contrast imaging instruments to facilitate detailed exoplanet characterization.

Promotor: Prof.dr. H. J. A. Röttgering, Co-Promotor: M. Haverkorn

Op deze pagina vind je de opnames van de Tuesday Talks sinds april 2025. Ook de opnames van de voorloper van de Tuesday Talks, This Week’s Discoveries, zijn hier te vinden

De lezing vindt plaats op woensdag 29 mei 2013 en is getiteld ‘Building stars, planets and the ingredients for life between the stars’. De Halley Lecture aan de Universiteit van Oxford is opgericht door de wijlen Henry Wilde, bij de terugkomst van de comeet Halley in 1910. De lezing wordt jaarlijks…

Growing planets one dust grain at a time

In Duitsland, Amerika en zelfs in Vietnam: overal ter wereld werd de Leidse ontdekking gedeeld van de geboorte van twee planeten. Astronoom Sebastiaan Haffert wist met zijn team voor het eerst meerdere planeten in wording vast te leggen en publiceerde zijn bevindingen in Nature Astronomy. Een unieke…

Astronoom Ignas Snellen besprak in Nature de opzienbarende ontdekking van zijn internationale collega's: een dwergster met zeven, op de Aarde lijkende planeten eromheen. Mogelijk zijn de omstandigheden er geschikt voor leven. Ook diverse media vroegen Snellen om commentaar.

Op donderdag 26 april gaf James Kasting zijn Oortlezing in het Academiegebouw. Kasting was twee weken in Nederland omdat hij was uitgenodigd als Oort Hoogleraar 2018.

Sterrenkundigen Ignas Snellen en Anthony Brown stonden met hun recentste ontdekking in De Telegraaf van 22 augustus. Ze wisten de massa van de pasgeboren exoplaneet Beta Pictoris b te bepalen. Hun ontdekking, die een publicatie opleverde in het blad Nature Astronomy, was zelfs het 'Nieuws van de dag…

Ewine van Dishoeck doet onderzoek naar water in de ruimte. Ze is gespecialiseerd in scheikunde tussen de sterren, zoals ze astrochemie zelf noemt. Onlangs publiceerde ze een groot overzichtsartikel van haar werk. ‘Ik voel het als een plicht voor de volgende generatie om dingen op een rijtje te zette…

De James Webb Space Telescope komt met zijn eerste foto van een exoplaneet: een planeet die draait om een andere ster dan onze zon. Astronomen zijn verheugd over het kiekje, dat planeet HIP 65426 b laat zien in niet eerder waargenomen golflengten. Ignas Snellen vertelt erover aan De Volkskrant.