קולוקוויום בחוג לגאופיזיקה: On Activity and Planets of Low-Mass Stars

Zoom: https://tau-ac-il.zoom.us/j/85032703038

Abstract:

Over the past 30 years, thousands of planetary systems have been discovered, mainly around low-mass stars (Mstar <1.2 MSun). The two primary methods used for this purpose are the transit and radial velocity (RV) technique. The former is sensitive to the planet's size, while the latter is sensitive to the planet’s mass, and together they enable the estimation of the planet’s density and, in some cases, even its atmospheric composition. However, stellar activity remains the primary factor limiting the detection and characterization of many more planets around nearby stars. In the last 6 years, my research group at Ariel University has been developing tools to discriminate activity from planets in high-resolution spectroscopic timeseries. Fortunately, activity-related variability differs from orbital Doppler shifts: it is usually incoherent, wavelength-dependent, and accompanied by variations in spectral shape. These differences can help us distinguish between activity-related and planetary signals, allowing us to model both phenomena simultaneously. We developed diagnostic tools, such as activity-index measurements and Gaussian Process (GP) periodogram analysis, and performed complementary photometric measurements. Additional tools are being developed to characterize transiting planets in terms of their internal structure and atmospheric composition. I will briefly review these efforts.

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מארגן האירוע: ד"ר ליאור רובננקו