May 14, 2021

The ExoExplorer Science Series on May 14 from 1-2 PM Pacific / 4-5 PM Eastern. Connection information is below.

Speaker: Jules Fowler (UCSC)

Title: Don't Heckle My Speckle: A Coronagraph Design Study for the SEAL testbed

Abstract: In the field of extreme adaptive optics (exAO), we seek to directly image exoplanets from the ground (often by extinguishing speckles of light due to system or environmental factors that may be brighter than the planet itself.) The Santa Cruz Extreme Adaptive optics Laboratory (SEAL) testbed will emulate the W. M. Keck Observatory, to develop and test novel instrumentation and algorithms concerning wavefront sensing, adaptive optics, and coronagraphy. Classical Lyot coronagraphs, in particular, present a fascinating opportunity for a design study, with a wealth of literature from the 2000s that can now be revisited and verified with high fidelity optical modeling using HCIPy. Similarly, Vortex coronagraphs offer improved light suppression while retaining the ability to image close-in companions. In this talk I present a design study for a Lyot and Vortex coronagraph optimized for the SEAL testbed. I will describe my simulations and optimization both in an idealized case and for a realistic case including wavefront, amplitude, and atmospheric errors. I will discuss my final designs for the coronagraph, plans for its implementation in our testbed, and future iterations of this work.

Speaker: Rachel Fernandes (U. Arizona - LPL)

Title: Exoplanet Demographics Beyond Kepler: Giant Planets with Radial Velocity & Young Planets with TESS

Abstract: The Kepler mission has provided detailed exoplanet population statistics for a large range of planet sizes close to their host stars. The first half of my talk will focus on how the completeness-corrected giant planet (~5-20 Re; ~0.1-20 Mj) occurrence rate from Kepler compares with that from the Mayor et al. 2011 radial velocity survey. I will also discuss the discovery of a break in the radial velocity giant planet occurrence rate and its implications for giant planets that be detected by direct imaging. The second half of my talk will focus on the Kepler’s short-period, small planet (~1-1.8 Re) population and how it affects estimates of EtaEarth, the frequency of habitable zone Earth-size planets. I will conclude by presenting our ongoing effort with TESS to de-contaminate the close-in small planet population from photoevaporated mini-Neptunes and thus provide more reliable estimates of EtaEarth.

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