Over 400 planets are known to orbit nearby, sun-like stars. These planets are called “exoplanets”. Professor Seager’s favorite exoplanet diagram is the mass-period diagram shown to the left. This diagram (updated monthly) shows that exoplanets have all masses and semi-major axes possible, showcasing the random nature of planet formation and migration. The different planet detection techniques are shown in the diagram. Parts of the diagram with no planets are where technology can not yet reach exoplanets.
The goal in studying exoplanet atmospheres is to understand the atmospheric composition and temperature. We want to be able to recognize planet atmospheres like Earth’s: with water vapor, oxygen, ozone, and carbon dioxide. These strong absorbers would make the major contributions to the spectrum we could observe from afar. While the detection of true Earth twins is some time off, we are busy trying to understand hot Jupiter and hot Neptune atmospheres observed by primary and secondary eclipses for transiting exoplanets. Professor Seager’s group’s research focuses on computer models of exoplanet atmospheres and interpretation of data from space telescopes.
Selection of Sara Seager’s most significant papers on exoplanet atmospheres
The first paper on hot Jupiter atmospheres
Seager, S., & Sasselov, D. D. 1998, “Extrasolar Giant Planets Under Strong Stellar Irradiation”, ApJ, 502, L157-161.View PDF
The first description of exoplanet transmission spectra, that led to the first detection of an exoplanet atmosphere
Seager, S., & Sasselov, D. D. 2000, “Theoretical Transmission Spectra During an Extrasolar Giant Planet Transit”, ApJ, 537, 916-921. View PDF
Co-authored one of the first two independent detections of photons from an exoplanet atmosphere
Deming, D., Seager, S., Richardson, L. J., & Harrington, J. 2005, “Detection of Infrared Radiation from an Extrasolar Planet”, Nature, 434, 740-743. View PDF
General description of super Earth atmospheres, lead by Prof. Seager’s student Eliza Miller-Ricci
Miller-Ricci, E., Seager, S., & Sasselov, D. 2009 “The Atmospheric Signatures of Super-Earths: How to Distinguish Between Hydrogen-Rich and Hydrogen-Poor Atmospheres”, ApJ, 690, 1056-1067. View PDF