"Giant Planets, Tiny Stars: Producing Short-period Planets around White Dwarfs with the Eccentric Kozai-Lidov Effect"
Alexander Stephan (OSU Astronomy)
Over the last few decades, a multitude of surveys have revealed that planets are commonly orbiting other stars, in a wide variety of orbital configurations often very different from our own solar system. Furthermore, such exoplanets have also been found orbiting stars with a large range of masses and at all phases of stellar evolution. Of particular interest here has been the discovery of so-called "polluted white dwarfs", white dwarf stars showing heavy elements in their atmospheres accreted from planet debris. These objects provide us with the opportunity to determine the bulk composition of exoplanets, but in most cases only rocky planet compositions have been observed. Recently, however, two systems have been discovered (WD J091405.30+191412.25 and WD 1856+534) that harbor gas giant planets closely orbiting their white dwarf host stars, too close, in fact, to survive their host stars' evolution at the current orbit. I will show how these gas giants can have reached their current orbits due to a dynamical mechanism called the "Eccentric Kozai-Lidov" effect, and I will discuss some of the information we can gain about general exoplanet formation and evolution from the existence of these planets.
"Large Scale Structure Cosmology from Weak Lensing and Galaxy Clustering"
Jack Elvin-Poole (OSU Physics)
Cosmological observations point to a universe with accelerated expansion, dominated by a cosmological constant and cold dark matter (The Lambda-CDM model). This model has been tested with obervations of early-universe (CMB, BBN, BAO) and late-universe (lensing, distance ladder) physics. Recent observations from The Dark Energy Survey (DES), the KiDS collaboration and BOSS/eBOSS have used galaxy clustering and weak gravitational lensing as a stress test of this cosmological model so far without definitive evidence for inconsistancies within Lambda-CDM or with other probes. I will review the status of these large scale structure results and preview what to expect from the upcoming DES Year 3 analysis. I will discuss the hurdles facing the current generation of LSS analyses and how to prepare for future surveys (Roman, Euclid, LSST/Rubin, DESI)