The Institute of Astronomy (IoA) of Leuven University in Belgium is a young and vibrant research group of some 80 scientists, engineers, and administrative staff (fys.kuleuven.be/ster), including 7 full-time and 3 part-time professors. The institute is an expertise center in stellar physics and is active in several international consortia and collaborations. All members of IoA have access to parallel and supercomputing facilities. The IoA is further responsible for the organisation of the 2-year Master program in Astronomy & Astrophysics of the Faculty of Science, and operates the 1.2m Mercator telescope at Roque de los Muchachos, La Palma Observatory, Canary Islands.
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Project
Project 1: Wind–Planet Interactions in Systems with Cool Evolved Stars
Planets orbiting cool evolved stars experience a radically different environment than those around main-sequence stars, as intense stellar winds, high mass-loss rates, and extended atmospheres can strongly affect planetary atmospheres. This PhD project aims to investigate wind–planet interactions in systems with cool evolved stars, focusing on how stellar outflows shape planetary atmospheric structure, chemistry, and long-term evolution. The research will combine hydrodynamical modelling of stellar winds and planet–wind interactions with radiative transfer and atmospheric chemistry, and will be closely connected to current and upcoming observations from facilities such as ALMA, JWST, and Gaia. By exploring a largely uncharted regime of planetary systems, this project will provide new insights into the fate and observability of planets around aging stars and will contribute to a broader understanding of star–planet interaction physics.
Project 2: Theoretical Modelling of Mass Transfer and Orbital Evolution in Eccentric Binaries with Cool Evolved Stars
The orbital evolution of binary systems containing cool evolved stars is governed by coupled, time-dependent processes of mass transfer, mass loss, and angular momentum exchange, yet a predictive mathematical framework for these interactions—particularly in eccentric orbits—remains incomplete. This PhD project will develop and analyse theoretical models describing the secular evolution of binary orbits under non-conservative, phase-dependent mass transfer, with explicit treatment of angular momentum budgets and their impact on semi-major axis and eccentricity evolution. The research will focus on formulating and solving systems of differential equations that capture the interplay between orbital dynamics and mass exchange. By exploring a wide range of binary configurations, the project aims to build a physically motivated framework for understanding how binary orbits evolve during the late stages of stellar evolution, and to provide theoretical insight relevant to the interpretation of observed evolved binary populations.
Profile
PhD applicants should hold a MSc degree in astrophysics, physics, and/or mathematics, or else have obtained an equivalent diploma by the time the PhD project starts. Proficiency in English (written and oral) is required. Interests and knowledge in stellar astrophysics, and/or computational (astro)physics are strong assets. The ideal applicants are committed and curious, have strong problem-solving skills, are proficient in programming, can integrate and work in a research team, and are eager to work at the forefront of scientific research and to develop their physical intuition.
Offer
The preferred starting dates for the positions are September-October 2026.
The successful PhD applicants will register at the Arenberg Doctoral School of KU Leuven and follow a doctoral program including personal training in management, science communication, and teaching. As part of the doctoral requirements, the candidates will spend up to 20% of their time for service duties, such as teaching and supervision in one of the Bachelor (in Dutch) or Master (in English) programs and performing Mercator observing runs of ten nights for the pooled IoA long-term monitoring programs.
The selected PhD candidates will be offered a 1-year bursary contract, renewable for up to 4 years after a positive evaluation. The tax-free bursary amount will be equal to the net salary of a research assistant (salary scale 43) and will be calculated upon joining KU Leuven. In addition, you will receive a generous package of pay and non-pay benefits, including a holiday bonus, end-of-year bonus, holiday allowance, free hospital insurance, free public transport when commuting, a bicycle allowance, staff discount scheme, access to our sports and cultural facilities at special rates, etc.
Interested?
The application should be received by March 15th, 2026.The shortlisted applicants will be invited for an interview in April 2026.
The application package should include:
(i) a curriculum vitae, with a publication list if relevant. On the last page, it should include the names and email addresses of two reference persons (references letters are NOT required at this stage; these will only be asked for the short-listed candidates);
(ii) a statement of interest explaining the motivation of the candidate for pursuing a PhD, the specific research interests of the candidate, and how these relate to past research experiences, the specific PhD position, and future goals (max. 1 page). The first sentence should clearly state which PhD positions the applicant is applying for.
(iii) a summary of the research experience (max. 2 pages, excluding references);
(iv) a transcript of all university courses taken and grades obtained to date.
For more information please contact Prof. dr. Leen Decin, mail: [emailprotected], or Mrs. Clio Gielen, mail: [emailprotected].
KU Leuven strives for an inclusive, respectful and socially safe environment. We embrace diversity among individuals and groups as an asset. Open dialogue and differences in perspective are essential for an ambitious research and educational environment. In our commitment to equal opportunity, we recognize the consequences of historical inequalities. We do not accept any form of discrimination based on, but not limited to, gender identity and expression, sexual orientation, age, ethnic or national background, skin colour, religious and philosophical diversity, neurodivergence, employment disability, health, or socioeconomic status. For questions about accessibility or support offered, we are happy to assist you at this email address.
Belgium
KU Leuven
On Campus (Full Time)
See Position Description
PhD Research Funding
March 15, 2026
On Campus (Full Time)