[PLS] Victoria DiTomasso (Harvard CfA)

“Hunting for a Standout Long-Period, Small Exoplanet, and for a Population of Ancient Jovian Worlds”

I will present two unpublished works. The first is the discovery of HD60779b, a long-period sub-Neptune. The structures of sub-Neptunes, as well as how mass loss has contributed to shaping their population, remain open questions. In order to answer them, we will need to observe these planets’ atmospheres and probe mass loss through observations of atmospheric escape. I will describe the 4-year-long journey to discover this 3.2 Earth-radius planet on a 30d orbit around a sun-like star, as well as its unique accessibility for follow-up observations. The second work aims to uncover a sample of old exoplanets in order to study planet formation in the young galaxy. The Milky Way’s thick disk stars, which are old (>9 Gyr), iron-poor, and alpha-enhanced, formed in a vastly different galactic environment than their younger, thin disk counterparts – impacting protoplanetary disk lifetimes and planet outcomes. I sought to identify a sample of planets around thick disk stars with which to test these predictions, a challenge given the relative scarcity of thick disk stars in the solar neighborhood. Hot Jupiters, with their large transit depths, are the most accessible population to study around thick disk stars, as TESS can detect them to large distances. I measured [Fe/H] and [alpha/Fe] abundances for a sample of candidate and known hot Jupiter hosts. From this sample, I identified two confirmed hot Jupiter host stars and three candidate hot Jupiter host stars as members of the thick disk.

Planetary Lunch Seminar:
Topics span the range of the EAPS planetary sciences research program and are intended to appeal to any graduate students, postdocs, research scientists, and faculty with a background in planetary science. Speakers include members of the MIT community and visitors.

Contact: planetary-org@mit.edu