Sean O'Brien

Astrophysics PhD Student at Queen's University Belfast

Planet Hunters NGTS
During my PhD, I am leading the data analysis of the Planet Hunters NGTS citizen science project. Exoplanet detection using transit surveys relies on many hours of human vetting to search for transit-like signals and filter out false positives. The power of citizen science has been proven by projects such as Galaxy Zoo, Planet Hunters and Planet Hunters TESS. These platforms present images or light curves from telescopes and utilise classifications from public volunteers to categorise astronomical phenomena, drastically increasing the speed at which researchers can discover new objects such as transiting exoplanets. My research is focused on exoplanet detection and measuring the detection efficiencies of the citizen science project hosted at Planet Hunters NGTS is the next iteration of the Planet Hunters project, using data from the Next-Generation Transit Survey to search for exoplanet candidates missed in the initial searches by the science team.


Prior to starting my PhD at Queen's, I studied for a BSc in Mathematics, followed by an MSc by Research in Physics, at the University of Warwick. For my Master's project, I investigated the noise propeties of scintillation-dominated light curves from the NGTS telescopes. Atmospheric scintillation is caused by light passing through turbulent regions of the Earth's atmosphere, resulting in changes in intensity of the light received by a telescope. This is more colloquially known as the "twinkling" we see when observing stars with the naked eye.


Scintillation-limited photometry with the 20-cm NGTS telescopes at Paranal Observatory
Sean M. O'Brien, Daniel Bayliss, James Osborn et al. 2022, MNRAS, Vol. 509, Issue 4, Pages 6111-6118, doi:10.1093/mnras/stab3399

Research Interests

  • Exoplanets detection
  • Exoplanetary system characterisation
  • Atmospheric scintillation


I enjoy participating in outreach activites, both specific to the Planet Hunters NGTS project (for which you can read my various blog posts here) and events in the wider context of promoting astrophysics, such as creating videos for the NI Science Festival (see below!)

NI Science Festival

Astro News Bulletin. Including an advert for Planet Hunters NGTS which you can watch in this standalone clip here: Planet Hunters NGTS advert.