Hi, I'm Gemma!

Astronomy PhD Student
at the University of Hertfordshire

About Me

Hi! I'm Gemma and I'm a third-year astronomy PhD student at the University of Hertfordshire. My PhD project is called "the exoplanet brown dwarf connection – ultracool companions to Gaia stars", and I've also done some work with the GUCDS team during the research parts of my undergraduate degree. The main research area that I'm interested in is ultracool dwarfs but I'm also interested in exoplanets (and always appreciate the pretty pictures of star-forming regions and galaxies!) I graduated from Hertfordshire with my undergraduate MPhys degree in 2022, with 1st Class Honours, and have stayed at Herts to continue my research journey!

Besides astronomy, I love travelling, Formula 1 and my cars Toby (seen in the photo here) and Bingo. I studied at Oklahoma State University for a year during my undergraduate degree, and I'm excited to have the opportunity to attend conferences in new places during my PhD!

Information

Name Gemma Cheng

Email g.j.cheng@herts.ac.uk

Address Centre for Astrophysics Research,

University of Hertfordshire, Hatfield, AL10 9AB

RAS

Member

3rd Yr

PhD Student

1st Class

MPhys Astrophysics (Hons)

EAS

Member

Current Research

Gaia Ultracool Dwarfs:
Candidate Classification

Observations of Gaia ultracool dwarf candidates have been obtained using the IRTF's SpeX instrument and Blanco's ARCoIRIS instrument. The data is reduced and the spectrum of each object is plotted to classify their spectral types. SpeXtool is used to reduce the SpeX data, and Splat is used to classify the candidates spectroscopically. From spectral analysis and colour-magnitude diagrams, candidates of particular interest have been identified for future further investigation, including young objects and potential binary objects.

Ultracool Dwarf Companions
to Gaia Primary Stars

Since their discovery 30 years ago, T-dwarfs have been an area of interest due to their low masses and cool atmospheres; but the properties of lone brown dwarfs are notoriously hard to determine. By finding T-dwarfs that are part of wide binary systems with Gaia-detected stars, we can infer characteristics like their age from the primary star, helping us calculate other properties and building a better picture of the physics of T-dwarfs. By creating a catalogue of these T-dwarfs along with their properties like mass, age and metallicity, we can use them as benchmarks to improve our models of brown dwarfs.