Steph Merritt

Postdoctoral Research Fellow at Queen's University Belfast

In Preparation for the Legacy Survey of Space and Time

The upcoming Legacy Survey of Space and Time (LSST) on the Vera C. Rubin Observatory is expected to drastically increase our knowledge of the solar system, with over ~6 million new planetesimals expected to be discovered during the course of its ten-year mission. This unprecedented survey of the night sky brings with it unprecedented challenges. A vast amount of community software is in the process of being created for the exploration of the immense amounts of data this survey will produce. I am currently involved in the development of a survey simulator for solar system objects which will enable astronomers to understand the observational biases present in the survey by comparing synthetic model populations with actual observations, allowing better predictions to be made of various population statistics.

Additionally, the autonomous solar system processing pipeline for the LSST will be incapable of linking and thus identifying objects which do not move a discernible amount in the course of a night, rendering it blind to the population of objects beyond about 100AU. The handful of objects previously found on this extreme edge of the solar system are too distant to be gravitationally affected by the giant planets, yet they show peculiarly eccentric orbits. Acquiring a larger sample of such objects is vital in determining which of several potential scenarios is responsible for these orbits: with one such scenario being the existence of an as-yet-unknown planet beyond the Kuiper belt, the hypothesised Planet Nine. I plan to lead the development of a public, open-source slow-moving object pipeline capable of detecting such objects from LSST data, facilitating a community effort to better understand the furthermost reaches of our solar system.

Exploring the Atmospheres of Alien Worlds

Of the many kinds of exoplanets discovered orbiting distant stars, those known as ultra-hot Jupiters provide a fascinating opportunity to explore their atmospheres. These Jupiter-sized gas giants orbit extremely close to their parent stars, and their atmospheres, with temperatures in excess of 2500K, are laboratories for extreme atmospheric physics. Lacking the clouds that often plague cooler exoplanets, their clear atmospheres are also relatively easy to characterise. Exploration with the high-resolution Doppler spectroscopy technique, which uses the planet's high orbital speed to separate its spectral lines from the host star, has revealed a wealth of atomic species in their gaseous form. During my PhD I extensively characterised the atmosphere of the ultra-hot Jupiter WASP-121b using this technique, leading in the development of a software pipeline that would perform this formerly computationally-intensive task with unprecedented swiftness, and I now plan to make this pipeline publicly available.


I graduated with a first-class honours undergraduate MSci in Physics with Astrophysics from Queen's University Belfast in 2016, and I completed my PhD in exoplanet atmospheres at the same institution in 2021. As a disabled, working-class, LGBTQ+ astronomer, and as a former mature student, I am passionate about equality and diversity in STEM and about uplifting non-traditional and marginalised voices. I am a member of the Maths and Physics Gender Equality Committee at QUB and have previous experience as a peer mentor and as a student representative. I also enjoy teaching, and I plan to bring my substantial PhD experience as a teaching assistant and demonstrator to new teaching roles in the 2022-2023 academic year.