THIRSTEE sample distributed in radius vs mass (left), equilibrium temperature (middle), and stellar effective temperature (right). Blue markers represent planets with an existing mass measurement in the literature and red markers represent those without one. TOI-406 b is shown in purple because this work represents the planet’s first mass measurement. Marker symbols correspond to the instruments the THIRSTEE survey is using to measure the mass of each planet. Underlying contours show the relative population of confirmed planets with better than 25% measurement precision in mass, according to data from the NEA accessed on August 27, 2024. Left: THIRSTEE targets without mass measurements are shown as bars, representing the range of their expected mass given their radius (e.g. Parviainen et al. 2024a). Curves representing an Earth-like and a pure iron composition are shown for reference (Zeng et al. 2019). Middle: equilibrium temperature taken from the literature where available. If unavailable, it was calculated assuming perfect day-night heat redistribution and zero Bond albedo. Right: for unconfirmed planet candidates, stellar effective temperature taken from the TICv8.