[Phys-seminars] 2017-01-11

griv griv at bgu.ac.il
Sun Jan 8 16:06:35 IST 2017



 DATE: 11-01-17

 TIME: 11:15

 PLACE: Seminar Room 207, Building 54

TITLE: 
Science with Orbital Phase Curves in the Space Age

SPEAKER: 
Dr. Avi Shporer, California Institute of Technology

ABSTRACT/COMMENTS: 
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 the science I am doing with phase curves. This includes using phase curve variability to detect non-eclipsing systems, which can transform photometric surveys like Kepler to the equivalent of a radial velocity survey. Another important application is the mass measurement of hot Jupiters orbiting hot early-type stars, where the mass cannot be measured using radial velocities. In addition, using phase curves of tran
 siting hot Jupiters I showed that the atmospheres of most such exoplanets have their optical brightest region shifted Westward of the substellar point, indicating an inhomogeneous cloud coverage. Finally, I will present a Keck/HIRES project focused on high-eccentricity binary stars identified in Kepler phase curves (aka heartbeat stars). As a whole, the above shows the high scientific potential of the study of space-based phase curves, which we have only begun to explore in recent years and will continue using data from current and future space-based surveys including K2, TESS, and PLATO.


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