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Photo of Dr Lewis Ireland

Dr Lewis Ireland

Postdoctoral Research Fellow

Email:

Telephone: 01392 724124

Extension: (Streatham) 4124

I am an Astrophysics Postdoctoral Research Fellow at the University of Exeter, working with Sean Matt as part of the ERC-funded project AWESoMeStars. I predominantly work with magnetohydrodynamic (MHD) simulations of star-disk interactions, using PLUTO to model magnetic interactions between young protostellar objects and their surrounding accretion disks. The goal of the AWESoMeStars project is to "develop a comprehensive, physical description of the origin and evolution of stellar rotation, magnetic activity, mass loss, and accretion".

I was awarded my PhD in October 2018 (supervisor: Matthew Browning), researching stellar structure and evolution, in particular how these are affected by magnetic fields and rotation. I have experience in 1D stellar structure evolution modelling using MESA, 2D spectral hydrodynamical and 3D magnetohydrodynamical numerical simulations, using Dedalus and Rayleigh, respectively. Rotation and magnetism are both known to influence convection: the velocities, temperature gradients, and spatial structure that prevail in a magnetised, rotating flow are generally different to those without these mechanisms. My project aim was to calibrate a mixing length theory (MLT) parameter in 1D models to mimic inhibitive effects, e.g., rotation and magnetism, on convective heat transport, through modified MLT prescriptions and comparison with 3D convection simulations. I monitored how the entropy content and radius of a star is sensitive to these changes, and whether they account for radii discrepancies between low-mass observations and standard 1D models.

Publications

  • Ireland, L. G., Zanni, C., Matt, S. P., & Pantolmas, G. (2021). Magnetic Braking of Accreting T Tauri Stars: Effects of Mass Accretion Rate, Rotation, and Dipolar Field Strength. The Astrophysical Journal, 906(1), 4. https://doi.org/10.3847/1538-4357/abc828
  • Ireland, L. G., & Browning, M. K. (2018). The Radius and Entropy of a Magnetized, Rotating, Fully Convective Star: Analysis with Depth-dependent Mixing Length Theories. The Astrophysical Journal, 856(2), 132. http://doi.org/10.3847/1538-4357/aab3da