Tuesday

The mass and density of a planet’s core tells us about the core ice-mass fraction, a direct connection to the formation process. In most cases the gaseous envelope hides this core, meaning we cannot determine its composition. In situations where the planet is exposed to intense radiation, that gaseous envelope may be lost, providing us with a unique opportunity. I will describe current results and motivation for the NCORES program, a HARPS campaign to characterise TESS-discovered planets orbiting close in to their host stars where photoevaporation can play a dominant role. To date NCORES has led or contributed to precise mass and density determination of 20 TESS planets smaller than 4R_earth, making a significant contribution to the Level 1 science goal. NCORES aims to produce a well-characterised sample of bright TESS planets to enable the study of close-in planets and cores on an individual and population level. I will discuss some key results from the program, including TOI-849, the remnant core of a giant planet, and multi-planet systems such as TOIs-125, 431 and 1233.