With the rapidly increasing number of newly discovered exoplanets, the characterization of their atmospheres is becoming the new frontier, crucial for distinguishing between different planetary populations and bearing the imprints of planet formation and evolution. To this end, transit spectroscopy has been the most fruitful technique, revealing the atmospheric species for dozens of exoplanets, mostly hot Jupiters. JWST is expected to advance this field with unprecedented precision and broad wavelength coverage, focusing primarily on the infrared where molecular absorption dominates. In 

this talk, I will present the results of our optical transmission spectroscopy surveys obtained with the GTC and the Palomar 200-inch telescope. I will highlight the synergistic role of the optical band in distinguishing stellar contamination and in constraining chemical abundances and cloud properties of planetary atmospheres. I will also show the great power of combining low-resolution spectrophotometry and high-resolution spectroscopy in constructing the vertical abundance and temperature profiles. Finally, I will discuss the emerging trend in atmospheric properties based on a retrieval framework homogeneously applied to a hot Jupiter sample.

BIO

Dr. Guo Chen is an associate research professor at Purple Mountain Observatory. He received his PhD from the University of Chinese Academy of Sciences in 2014. He visited Max-Planck Institute for Astronomy in Germany as an exchange student from 2010 to 2012, and worked as a postdoc at Instituto de Astrofísica de Canarias in Spain from 2015 to 2018. Dr. Chen’s research interests focus on the observational characterization of exoplanet atmospheres, mainly based on transit spectroscopy and Doppler spectroscopy.