NRF Women's Month 2026: Nkateko Baloi

Every research journey starts with a question. This Women’s Month, the NRF celebrates women driven by curiosity — researchers whose questions, ideas and determination are expanding our understanding of the world around us. From exploring the unknown to deepening our existing knowledge, curiosity remains at the heart of discovery. We thank all participants for sharing their stories with us.

Ms Nkateko Baloi is a Master’s student in Astrophysics and Space Science at the University of Cape Town (UCT). Her funding journey with the NRF started in her second year BSc through the  South African Radio Astronomy Observatory (NRF-SARAO), and she is currently funded for her Master’s studies. Her research focuses on using machine learning to find planets that orbit the stars outside our solar system.

How has your affiliation with the NRF impacted your studies/career?

I have been funded by the NRF since the second year of my BSc in Astronomy at the University of the Witwatersrand. I was first funded by the South African Radio Astronomy Observatory (NRF-SARAO) through their undergraduate block grants from 2022 to 2023. I was then funded again by NRF-SARAO during my BSc Hons in Astrophysics and Space Science at the University of Cape Town in 2024. Thereafter, I was funded by the NRF through the National Astrophysics and Space Science Program (NASSP) for my MSc in Astrophysics and Space Science. I also received a bursary from the NRF through the General Master’s scholarship this year.

The funding I have received throughout my undergraduate and postgraduate studies has allowed me to pursue my studies with financial security. This reduced the already massive amount of stress that comes with pursuing a career in the sciences. And this funding allowed me to relocate from Johannesburg, my hometown, to Cape Town, where I had to learn to live on my own for the first time.

As an Honours student in 2024, my academic achievement granted me the opportunity to attend the end-of-year NRF-SARAO postgraduate conference, which is typically available only to postgraduates pursuing their Master’s and above. The accommodation, travel, and food expenses were all paid for by NRF-SARAO. This was the third conference I was able to attend that year. The first was the NRF-SARAO undergraduate conference in Cape Town, and the second was the IAU-GA, also held in Cape Town. I volunteered at the IAU-GA, which allowed me to attend through the NRF’s grant scheme at the time.

I have received many opportunities through the NRF that I would never have had access to otherwise.

What is your research focus or area of expertise?

My research focuses on using machine learning to find exoplanets. Exoplanets are planets that orbit stars outside our solar system. There are several ways to detect these planets using both ground-based and space-based telescopes. For my project, I use the KELT-South telescope, a ground-based telescope in Sutherland.

KELT-South is one half of a pair of telescopes, with KELT-North located in the northern hemisphere. The telescope images the night sky over several days, and as those images are captured, the data are collected and stored in files. This data includes the time each image was taken and the brightness of the stars. I then visualise these data using Python. The collection of data points plotted against time is called a light curve.

We search for planets by analysing the shape of the light curve. When a planet crosses in front of its star along our line of sight, the star’s light curve shows a U-shaped dip. This detection technique is known as the transit method, and the transit is the portion of the light curve during which the planet passes in front of its star.

During the process of analysing these light curves, astronomers use mathematical models such as Box Least Squares. This model approximates the expected transit shape, and the resulting features provide information about the planet’s orbital period, size, and distance from its star. In this way, scientists can build a picture of a planetary system without directly observing it.

However, these traditional methods are not always accurate and often require a team of astronomers to confirm whether a transit is real. They are also time-consuming, especially as modern telescopes continue to discover more planets. This is why machine learning is so valuable: it can process many more light curves and, in some cases, with greater accuracy than traditional methods. It can also classify light curves using appropriate labels from the literature, which significantly reduces the time between identifying a potential planet, making follow-up observations, and confirming a detection.

My project aims to compare the success rates of traditional methods and machine learning in correctly identifying known exoplanets observed with the KELT-South telescope, while also exploring the possibility of discovering planets that were previously missed. My expertise lies in both exoplanet science and computational science. This includes literature-based knowledge of how planets form and the types of planets we might expect to recover from these observations, as well as the application of machine learning and data analysis techniques.

South Africa does not have a formal way of studying planets, as there are no exoplanet researchers in the country. I have yet to let that stop me from pursuing my passion in exoplanet science. One of the ways I have kept myself in the loop of the planet world is by completing a three-month summer internship at the Max Planck Institute for Astronomy, where I worked on a research project aimed at studying clouds in exoplanet atmospheres and focused on modelling their emission spectra using the MSG model, which is a cloud model.

At the end of my internship, I delivered a scientific talk to the department, explaining my work, which involved the use of a Python package called petitRADTRANS to re-model the emission spectra of the simulated exoplanets developed by my supervisor. My daily routine included networking with colleagues during morning ‘science coffee’ sessions, attending seminars by institute researchers, participating in journal clubs on exoplanet atmospheric research, and listening to shorter colloquia on recent advances in the field during ‘Exocoffee’.

These collective experiences connected me with current scientific developments and have encouraged my ongoing engagement in the scientific community, where I continue to attend the ‘Exocoffee’ sessions online and have attended the monthly ‘Habitable Worlds’ meetings via Zoom.

The opportunities to study exoplanets are there for the taking, but sometimes one has to create them. One such example in my journey came during my final year of my BSc at Wits University. I asked my supervisor, Professor Rudolph Erasmus, whether he would be willing to change his project from materials science to exoplanets. Because his expertise was in spectroscopy, we were able to explore how spectroscopy is used to study planets. The time I spent on that project sparked my interest in the field and carried me into my Master’s degree. That project did not end with me either; it has been available to third-year students ever since and continues to inspire others to pursue exoplanet science.

What sparked your curiosity about your field of research, and what continues to keep you curious?

I was first drawn to astronomy by my curiosity about how the universe works. I wanted to understand how things became the way they are, and whether they had always been that way. I also wondered how ancient civilisations made sense of the world around them without the physics knowledge we have today, and how our research methods have evolved over time.

The branch of astronomy that continues to fascinate me most is exoplanet science. It offers many avenues for exploration, from planet detection with telescopes to atmospheric studies that involve chemistry. The field is so broad that no one can fully master it all, especially without understanding the instrumentation that makes these observations possible. I would love to know as much as possible, but it is the study of exoplanet atmospheres and planetary environments that has kept me focused on the search for Earth-like worlds.

I am also interested in how life might form on other planets, which means engaging with biology as well. Fortunately, astrobiology brings these disciplines together. The intersection of astronomy, engineering, chemistry, and biology makes exoplanet science, in my view, one of the most fascinating fields in science.

What is one thing you wish more people understood about your field of research?

It is tempting to think that exoplanet scientists are only interested in aliens, but in reality, we are interested in all life forms that could exist in any pocket of the universe. We also hope that in this vast universe, we are not alone.

It should be known as well that some exoplanet scientists are not focused on searching for life beyond our solar system. Many are fascinated by the planets that exist in other solar systems but have no equivalent to our own, such as Hot Jupiters and Sub-Neptunes, sometimes referred to as “water worlds”. Others are more interested in the formation history of planetary systems and aim to build models that help explain how these systems come to be.

Planets are more than large rocks in outer space; they are part of the puzzle of understanding how the universe works.

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