Image: Erin Higgins
Astrophysicist Dr Erin Higgins explains why our sun is in fact a very ordinary star and why it’s important to study the most massive stars in the universe.
Dr Erin Higgins is an astrophysicist who works at the Armagh Observatory and Planetarium, where she researches the lives and deaths of the most massive stars in the universe.
Higgins has a bachelor’s degree in physics with astrophysics at Queen’s University Belfast and a postgraduate certificate in education to teach secondary-school physics. She was awarded a Lindsay PhD scholarship to complete her PhD at Armagh Observatory and Planetarium in conjunction with Dublin Institute for Advanced Studies, as part of a cross-border collaboration.
As part of her work, she collaborates with astronomers in the BRIDGCE UK Network to understand how elements necessary for our daily lives are formed in the cores of stars and are ejected in their strong winds or supernovae deaths.
She is also a representative for the Institute of Physics initiative, Project Juno, which encourages gender equality in STEM subjects, and works with the public and schools as part of its education and outreach programme.
Tell us about your current research.
My research is based on the structure and evolution of stars. I calculate complex simulations which track their lives, so that we can better understand the physics that drives their evolution, and what dictates their eventual fates as black holes and supernovae.
‘The most massive stars in our universe have been discovered to weigh up to 300 times the mass of our sun’
In recent years, I have used theoretical models to better understand observations of stars in the nearby Magellanic Clouds, which are dwarf galaxies that are very close to our Milky Way galaxy.
Most recently, I have been working on the nucleosynthesis (creation of elements) in stars so that we can trace the chemical enrichment of our local neighbourhood with the elements that were necessary to form the metal-rich environment we now live in.
Our sun, while crucial for our daily lives, is quite an ordinary star. It was born in a star-forming nursery called a nebula. It burns hydrogen into helium in its core by forcing atoms together, creating heavier and heavier elements. The most massive stars in our universe have been discovered to weigh up to 300 times the mass of our sun, and while they were born in the same nebula, they evolve very differently.
These stars are extremely efficient nuclear fusion reactors, which manufacture the heaviest elements of all. With blistering surface temperatures, they experience strong winds that carry billions of kilograms of material off their surfaces, leaving behind an exposed core with only a small fraction of the star remaining.
With a final burst of energy, these once massive stars explode in spectacular supernovae, shining brighter than an entire galaxy full of stars, leaving behind a black hole. In these supernovae deaths, brand new elements are forged and littered throughout the neighbouring space.
Throughout the lives and deaths of the most massive stars, they enrich our universe with the ingredients necessary to form the next generation of stars with their own solar systems. In fact, these stars were responsible for making the silicon in our mobile phones, the aluminium in our cars, the gold in our jewellery and everything else on our planet.
A few billion years ago, our sun formed from the ejected material of other stars. The leftovers then formed the planets in our solar system, and eventually, us.
This means that the carbon, of which all life is made, the iron in our blood and the calcium in our bones all came from the atoms which were previously in the cores of stars.
With our research, we can track how much of each element is produced in the cores of different types of stars and how much is ejected into the nearby space through stellar winds.
In your opinion, why is your research important?
Astronomy is the key to finding our place in the universe and understanding where we come from. We work as a global community and this unites nations in their quest to answer the big questions.
I research the nature of massive stars, from the origin of elements that are crucial for our daily lives, to the new technologies built in the pursuit of understanding black holes.
What inspired you to become a researcher?
When I was at school in Thornhill College in Derry/Londonderry, I was part of the astronomy club. I did a GCSE in astronomy and really enjoyed doing evening observations of Jupiter and its moons, so it was this interest, as well as encouragement from my teachers, that inspired me to pursue a career in astrophysics.
My parents bought me a 1-metre National Geographic telescope which I used to observe the Orion nebula and the craters of the moon, and this further developed my passion over several years.
Undertaking work experience at Armagh Observatory when I was 17 confirmed that this was the right path for me.
What are some of the biggest challenges or misconceptions you face as a researcher in your field?
Astrophysics has never been a 9-5 job, as it requires flexibility, but that means that we can work from anywhere in the world at any time.
Before embarking on a career in astronomy, I didn’t realise how many opportunities there would be to travel with work. It is common practice to move to another country every few years.
The research itself requires a lot of determination and working at the frontier of astronomy can be challenging when trying to solve a long-standing problem.
How do you encourage public engagement with your work?
I have presented at many careers events, both in person across NI and virtually, to many UK schools. Young audiences have been significantly impacted by this, with many undertaking work experience and demonstrating a keen interest in astronomy as a result.
During Covid, I attended virtual seminars to engage with representatives from Harvard University, the James Webb Space Telescope, along with other inspiring academics around the world. This led to the creation of a vibrant research group at Armagh Observatory and Planetarium that interacted regularly throughout the pandemic.
In 2022, I gave an astronomy lecture on ‘Black holes making ripples in space’ at Brian Cox’s Science Summer School, which hosted representatives from industry and technology across the UK for more than 400 young people.
The Festival EDU initiative ‘Our Place in Space’ developed a scaled model of the solar system, which allowed many people to learn about its planets in 2022.
Armagh Observatory and Planetarium has continued to host many public events, including the West Cork Music Festival, workshops for schools and stargazing evenings.
10 things you need to know direct to your inbox every weekday. Sign up for the Daily Brief, Silicon Republic’s digest of essential sci-tech news.
