Research Fellow · University of Auckland

Sean Richards

Computational astrophysics — binary stars, compact remnants, gravitational waves

I model how binary stars live, die, and kick their remnants across the galaxy — using the BPASS models, the STARS code, and the merger rates seen by LIGO and Virgo.

What I'm about

Binary evolution, remnant kicks, and the gravitational-wave sky.

I work with stellar models — primarily the BPASS models and the STARS code. I study compact remnant population synthesis and the nature of the natal supernova kick, using the observed merger rate densities from LIGO and Virgo to constrain the kick parameters — α and β for the Bray kick, and σ for the Hobbs kick.

I also have a strong interest in computational astrophysics. My background in Computer Science is what equipped me to take on large-scale stellar modelling, and I'm currently developing the BPASS v3 data release.

α
Bray kick
Fallback-scaling parameter linking ejecta mass to remnant kick strength.
β
Bray kick
Second Bray-kick parameter, fit jointly with α against merger-rate data.
σ
Hobbs kick
Velocity dispersion of the Maxwellian natal-kick distribution.

Tools of the trade

The models and observatories behind the work.

BPASS

Binary Population and Spectral Synthesis — the stellar population models at the core of my research, now heading toward a v3 data release.

bpass.auckland.ac.nz →

STARS

A detailed stellar-evolution code used to follow binary systems through mass transfer, core collapse, and remnant formation.

github.com/UoA-Stars-And-Supernovae/STARS →

LIGO & Virgo

Observed compact-object merger rate densities that I use to constrain natal-kick parameters against real gravitational-wave events.

Expertise

From first-year CS to full binary-physics modelling.

Bachelor of Science

Computer Science & Physics

Majoring in Computer Science, with an algorithmics and computability focus, and Physics, with an astrophysics focus.

Postgraduate Diploma in Science

University of Auckland Ground Station One

Worked with Te Pūnaha Ātea to help develop the University of Auckland's first ground station.

Master of Science

The Missing Mergers: Modelling the observed binary neutron-star population and their mergers

Worked with Professor Jan Eldridge to determine the nature of the natal supernova kick.

Doctor of Philosophy

The Next Generation: Refining the Standard Population Synthesis Model to Better Predict Stellar Population Properties

Working with Professor Jan Eldridge, Associate Professor Nick Rattenbury, and Dr Héloïse Stevance to more efficiently model the full physics of binary star systems.

Research Fellow — current

Full binary-physics modelling

Working with Professor Jan Eldridge, Dr Nick Rattenbury, and Dr Héloïse Stevance to more efficiently model the full physics of binary star systems.

Programming

Years of writing the code the models run on.

Python is my native language, but I've also worked in C, C++, C#, Lua, HTML/CSS/JS/jQuery, three generations of Fortran, PHP, and Julia.

Python C C++ C# Lua HTML / CSS / JS / jQuery Fortran 77 / 95 / 2003 PHP Julia
Kaitiaki
Takahe
glisten
MyBBWiki

See it all on GitHub →

Get in touch

Say hello.

Address

38 Princes Street
Auckland Central
Auckland 1010
New Zealand