Studying stellar variability – two varieties and their connection to fundamental stellar parameters
PhD defence, Friday 30 October 2026, Jens Reersted Larsen
During his PhD studies, Jens Reersted Larsen studied two forms of stellar variability and their respective connections to fundamental stellar parameters. The availability of fundamental stellar parameters is essential for our understanding of stellar lifecycles, the repercussions of which propagate to inferences drawn throughout astrophysics, such as galactic evolution and exoplanet characterisation.
The first type of variability investigated by Jens Reersted Larsen was stellar granulation, the overturning of convective material at the stellar surface. He examined how best to model and interpret the changing observational signals across regions of stellar evolution and developed a way to tie these signals to the underlying stellar radii. Secondly, he considered the asteroseismic signals of evolved giant stars. By building on existing methodologies, he enabled detailed characterisation of such stars using the observed individual oscillation frequencies, finding that such an approach is necessary to ensure reliable stellar parameters.
The PhD study was completed at the Department of Physics and Astronomy, Faculty of Natural Sciences, Aarhus University.
This summary was prepared by the PhD student.
Time: Friday, 30 October at 13:00
Place: Building 1525, room 626, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C.
Title of PhD thesis: From Stellar Variability to Fundamental Stellar Parameters
Contact information: Jens Reersted Larsen, e-mail: jensrl@phys.au.dk, tel.: +45 61778186
Members of the assessment committee:
Professor Dr. Markus Roth, Thuringian State Observatory Tautenburg, Germany
Assistant Professor Dr. Lisa Bugnet, Institute of Science and Technology, Austria
Lector Brian Julsgaard (chair), Department of Physics and Astronomy, Aarhus University, Denmark
Formal supervisor: Professor Hans Kjeldsen, Department of Physics and Astronomy, Aarhus University, Denmark
Academic supervisor: Lector Mia Sloth Lundkvist, Department of Physics and Astronomy, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English
The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C