Cloud Atlas of Directly-Imaged Exoplanets and Planetary Mass Companions

Thursday 5 July, 15:00

Rotational modulations that induced by the atmospheric heterogeneity offers an ideal way to isolate the effect of condensate clouds in the time-resolved observations. In the HST treasury program Cloud Atlas, we observed rotational modulations in a substantial number of brown dwarfs and directly imaged exoplanets, from which we constructed a statistically significant sample of ultra-cool atmospheres with vertical cloud structures determined. I will present latest results from HST program, with the emphasis on the successful applications of high-contrast, time-resolved observations of planetary mass companions and exoplanets. In these studies (Zhou et al. 2016, 2018), I measured rotational modulations in two planetary mass companions and calculated the vertical structures of the clouds in these objects. These objects show striking similarities to the spectral type matching brown dwarfs. With these observations, we took a key step in connecting the characterizations of brown dwarfs and exoplanets. I also led the development of HST/WFC3 ramp model RECTE (Zhou et al. 2017), which improves the data reduction quality for time-resolved observations and is adopted in multiple transiting exoplanet studies. In the era of JWST, we are going to apply this method with much sensitive and powerful instrument to start to spatially resolve the cloud structures for directly-imaged exoplanets.

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