June 17, 2022

The ExoExplorer Science Series presents talks by cohort members Aaron Carter (UCSC) & Aida Behmard (Caltech) on June 17, 2022, from 11 AM - 12 PM Pacific / 2 PM - 3 PM Eastern. Connection information is below.

Speaker: Aaron Carter (UCSC)

Title: Kickstarting a New Generation of Exoplanet Observations: Early Release Science with JWST

Abstract: Following the launch of JWST, in addition to a selection of ongoing commissioning activities, we now stand just months away from the beginning of scientific observations. Dispersed throughout these initial data will be a selection of Director’s Discretionary Early Release Science (ERS) observations which were designed under a primary goal of rapidly informing the community on JWST’s performance and capabilities. With respect to the study of exoplanets, only two ERS programs exist: “The Transit Community Early Release Science Program” (PI: N. Batalha, ERS-1366), and “High Contrast Imaging of Exoplanets and Exoplanetary Systems” (PI: S. Hinkley, ERS-1386). In totality, these two programs will set the tone for JWST exoplanet observations throughout its lifetime.
In this talk I will provide an up-to-date overview of both of these programs, the timelines for their data releases, and a description of their technical and scientific goals. Additionally, I will discuss existing and ongoing preparatory work towards the production of a range of science enabling products. These products (e.g. data reduction pipelines, analyses of best practices) are an integral part of the ERS programs and will support JWST investigations throughout Cycle 2 and beyond.

Speaker: Aida Behmard (Caltech)

Title: A Survey of Planet Engulfment Amongst Planet Host Systems

Abstract: Dynamical evolution within planetary systems can cause planets to be engulfed by their host stars. Following engulfment, the stellar photosphere abundance pattern will reflect accretion of rocky material from planetary cores by exhibiting refractory enhancements in order of condensation temperature $T_c$. Multi-star systems are excellent environments to search for such abundance trends because stellar companions share the same natal gas cloud and primordial chemical composition to within $\sim$0.05 dex. Thus, refractory differences above $\sim$0.05 dex that trend with $T_c$ between companions are a signpost of engulfment. Abundance measurements have occasionally yielded such engulfment signatures, but few observations targeted systems with known planets. To address this gap, we carried out a survey of 36 multi-star systems where one star is a known planet host with the Keck High Resolution Echelle Spectrometer. None of the 36 systems observed exhibit abundance patterns strongly indicative of engulfment events, which could be explained by our modeling efforts that show observable refractory enrichments from 10 $M_{\oplus}$ engulfment events are depleted on timescales of $\sim$1 Gyr for solar-like stars.

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