Transiting Exoplanets and Their Atmospheric Compositions

So far (Aug 2020), more than 75% (3191/4201) of exoplanets are discovered by transit. Transmission spectroscopy is the most popular method for studying the atmospheres of exoplanets. I contributed to a few studies with my expertise in high-precision Hubble Space Telescope (HST) time-series observations.

I (together with Prof. Daniel Apai and Dr. Ben Rackham) mentored an undergraduate student, Zhanbo Zhang, to re-analyze HST/WFC3 observations of TRAPPIST-1 planets. In this study, we corrected light curve systematics with the model RECTE, for which I led the development. From the combined spectrum of six of the seven TRAPPIST-1 planets, we demonstrated that the un-occulted stellar spots/faculae could introduce contaminating spectroscopic features. Therefore, understanding the stellar surface structures is crucial for accurately interpreting transmission spectra.

I am involved in a few other transmission spectroscopy studies, including the first discovery of escaping atmospheres from an exoplanet.

I am a co-I of an HST program studying close brown dwarf companions of white dwarfs. These brown dwarfs receive powerful radiations from the white dwarfs and behave similarly to hot Jupiters. However, the brown dwarf thermal radiation signals are much stronger than typical hot Jupiters. Therefore, these brown dwarf-white dwarf pairs are excellent test cases for hot Jupiter atmospheric theories.