Researches

Exoplanets Around M Dwarfs

With the highest planet-to-star mass ratio of any type of planetary systems, giant planets around M dwarfs are extreme cases that serve as sensitive probes of planet formation and bridges between theories for star and planet formation.

I am leading the GPASS (Giant Planets Around Small Stars) program, aimming to understand the formation and evolution of these rare systems. I have been working on confirming such systems through photometric and spectroscopic follow-up observations (Gan et al. 2022a, Gan et al. 2023a), estimating their occurrence rates (Gan et al. 2023b), measuring the obliquity of hot Jupiters around M dwarfs (Gan et al. 2024a), and studying the planet-metallicity correlation of such systems. I wish to expand these studies to cold Jupiters with Gaia astrometry (Gan et al. 2023c). I am interested in how the results of giant planets around M dwarfs differ with those FGK counterparts, for example the relative occurrence rates between hot and cold Jupiters (Gan et al. 2024b).

Apart from gas giants, I am also interested in small planets around small stars (Gan et al. 2020, Gan et al. 2022b).

Low-Mass-Star Characterizations

To better understand planets around low-mass stars, it is crucial to have well-determined stellar properties. Based on the TESS survey, I am working on characterizing a sample of transiting brown dwarfs and, in particular, low-mass M stars (Lin, Gan et al. 2023, Gan et al. in prep), to refine the isochrones towards the low-mass end.

Connection Between Exoplanets and Stellar Abundances

Is the Solar System special? To answer this question, I am involved in the PASTA (Planets Around Solar Twins/Analogs) Survey as a co-PI (Sun et al. in prep). Taking the solar spectrum as a template, I am working on measuring the chemical abundances of solar twins/analogs hosting planets through line-by-line differential analysis, and investigating potential connections between stellar elemental abundances and planet formation (Gan et al. 2021).