While the binary fraction of O stars has been characterised through interferometry, this is yet to be acheived for B stars. I have analysed PIONIER data of a sample of ~30 B stars, and find a high multiplicity fraction for the sample as well as the presence of a significant fraction of high-order systems. A paper is in preparation.

HD148937, a member of the rare Of?p class of massive stars, is a massive binary system. One star within the system is magnetic and the other is not, and its environment is not dense enough to make a capture event likely. Working with multi-epoch interferometric and spectroscopic data, we are characterising the orbital parameters of the system and determining the properties of the stars to investigate what mechanism induced the magnetism in only a single star. This result has now been published in Science.

As part of a multi-institute collaboration I handled interferometric data of the system HR 6819. The system gained significant media attention in 2021 with the claim that it was a triple system of stars, one of which was the closest detected stellar black hole to Earth. Our team obtained Directors Discretionary Time for the system and I reduced and analysed the interferometric data which allowed us to determine that no black hole exists in the system and that it is instead a rare post-interaction binary system. A letter led by myself was published in A&A, alongside an ESO press release, in March 2022. 

This project seeks to determine the origin of massive stellar multiplicity by studying forming massive stars, or massive young stellar objects (MYSOs). Using interferometric data obtained with GRAVITY, one star forming region M17 is being analysed to determine the separation and nature of young massive stars. This project is the subject of PhD student Emma Bordier’s thesis, who I co-supervise with Prof. Hugues Sana at KU Leuven. The first two papers of Emma's thesis have been published in A&A, and her final one is in preparation.

I have applied a multi-scale methodology to study in circumstellar environments of massive young stellar objects (MYSOs). By using a combination of infrared interferometry, imaging, spectral energy distributions and 3D radiative transfer modelling, the properties of the MYSOs are constrained at multiple scales and disk emission is distinguished from larger scale material. This method allowed the detection of an inner hole in the disc of an MYSO (Paper I, A&A) implying that something other than dust sublimation is disrupting material within the inner disk regions. When this method was applied to a sample of MYSOs (Paper II, A&A), we find that while all the sources are similar at larger wavelengths, their disks show variation; some have inner holes, some show more complicated spiral structure and some are uniform. Further combination of these geometrical results with an independent spectral analyses suggests that the kind of structure found in the disks correlates with their suspected age (Paper III, ApJ). 

As a member of the Instituut voor Sterrekunde at KU Leuven, I enjoy observing with the HERMES spectrograph at the KU Leuven-owned Mercator telescope. With my personal observing time, I obtained data to study the inner regions of Herbig discs using optical/infrared spectroscopy in collaboration with Dr. Alice Booth (Leiden Observatory) and Dr. James Miley (ALMA).