JJ Eldridge

Jan Jamie Eldridge
JJ Eldridge
Credit: inSCIght Magazine Photography.
All rights reserved. Used by permission.

Occupation: Theoretical astrophysicist

Research Areas: Numerical Modelling, Stellar Evolution, Binary Stars


"While we try our best to make our best models with our current understanding of physics, the most exciting time is when a new exploding star or merging gravitational wave source is seen which we didn't expect"

Source: New Zealand Herald


Early Life

JJ read and watched lots of science fiction when they were a child. They liked how the science was a part of the story. However, JJ didn't think about going to university until a career advisor suggested it.  

JJ went to the University of Cambridge, UK and to start with, studied maths, physics, chemistry and geology. After a year, JJ realised they really wanted to study physics. They were awarded her first degrees in science in 2001. JJ continued to study at Cambridge and in 2005, completed a PhD in astrophysics. JJ then spent time as a scientific researcher in Paris, France and in Belfast, Northern Ireland

Career Highlights

JJ is a Professor and Head of the Physics Department at The University of Auckland in New Zealand. JJ’s research focuses on the lives and deaths of stars in binary star systems. A binary star system contains two stars which orbit each other. This kind of star system is common in our galaxy. In fact, our Sun is one of the rare ones - over 75% of stars in the Milky Way are binary! The stars in these systems can get in each other's way. This makes it much harder for scientists to predict what the stars will do when they run out of fuel.  

JJ uses numerical models to study how the stars in binary systems evolve and change over time. A numerical model represents something in the real world using maths. Large, complicated models need powerful computers to run them. JJ created a unique computer code to help her model her area of research. The code is called Binary Population and Spectral Synthesis code. Scientists all over the world can use this code to study what happens when two stars interact with each other over time. JJ uses the code to model what will happen to binary star systems. They then compares the model to observations of stars in our own galaxy and in the wider Universe

JJ is also keen to increase the public's knowledge of and interest in science. They give talks to the public on topics from her research. In 2019, JJ and astronomer, Christopher Adam Tout, published a book called “The Structure and Evolution of Stars”. 


JJ is a non-binary trans woman. They work to make science and academia more diverse and more inclusive for LGBTQ+ people. In 2019, New Zealand's LGBTI Awards shortlisted JJ for the Hero of the Year Award. In 2021, JJ was named a New Zealand 'Woman of Worth' by MiNDFOOD and L’Oréal

JJ is a Fellow of the Royal Astronomical Society in the UK. They are also a member of the Astronomical Society of Australia and won their Anne Green Prize for a mid-career astronomer. JJ has also won an award for sustained excellence in teaching from the Faculty of Science at the University of Auckland.

Other Interests

JJ reads and watches sci-fi but has also given public talks on how accurate science-fiction is! JJ likes to relax by cooking or playing computer games. They keep fit by running, cycling and practicing Tae Kwon Do.