Seminar

Science with Orbital Phase Curves in the Space Age

February 28, 2019

Avi Shporer

We are living in the golden age of time series photometry, when high-quality data is delivered by space-based surveys for a large number of stars in visible light. This enables a detailed study of the minute variability following the orbital motion of stellar binaries and star-planet systems, at a precision which is beyond reach from the ground. These orbital modulations are induced by a combination of gravitational and atmospheric processes, hence the phase curve shape contains information about the companion’s mass and atmospheric characteristics. I will present some of the science done with phase curves (reviewed in details in Shporer 2017). This includes the investigation of hot Jupiter exoplanet atmospheres where in one study we showed that the atmospheres of many or even most exoplanets have their optical brightest region shifted Westward of the substellar point, indicating an inhomogeneous cloud coverage. In addition, phase curves potentially allow detecting non-eclipsing systems, which can transform photometric surveys like Kepler to the equivalent of a radial velocity survey. As a whole, the above demonstrates the high scientific potential of the study of space-based phase curves, which we have only begun to explore in recent years. I will conclude with a description of the NASA TESS Mission and the first study of a TESS phase curve of a hot Jupiter planet (Shporer et al., submitted).

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