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Abstract: This study will enhance our understanding of young exoplanet evolution by using stellar lithium (Li) abundances to estimate the ages of clusters, and thus the exoplanets located within them. Open clusters are collections of tens to hundreds of loosely gravitationally bound stars that formed at roughly the same time. All member stars in a cluster are born with some primordial lithium abundance, though it is rapidly depleted once a star reaches a certain core temperature. The more luminous stars in a cluster will reach this temperature first, and thus deplete their Li sooner. This will reveal a boundary between stars with and without lithium that occurs at a certain luminosity, known as the lithium depletion boundary (LDB). For this study, stellar spectra have been obtained for 61 stars in five young clusters via the South African Large Telescope (SALT). The spectra will be used to measure the Li absorption lines at the 6708 Angstrom transition, providing a direct indicator of lithium abundance. The data can then be used to find the LDB and allow us to use existing Li abundance models to infer the age of the cluster, and thus all exoplanets within it. Since the majority of interesting exoplanet development occurs in the first hundred million years, accurately dating these open clusters is key to understanding early exoplanet evolution.

Advisor: Professor Elisabeth Newton

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https://dartmouth.zoom.us/j/92161840277?pwd=uWI87w8mfXMrdQFeat4ZwsN1rKaqR2.1

Meeting ID: 921 6184 0277
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