Left: semi-major axis versus stellar radius of small USP planets (R_P < 2 R_⊕), where we highlight a lack of planets that cannot be explained through observational bias, $a⪅0.0085\text{}$ au (1.8 R_⊙) and ${\text{R}}_{★}⪆0.5\hspace{0.17em}{\text{R}}_{\odot }$. The dotted grey lines trace iso-probability transit regions. Right: orbital period scaled to the Roche limit for USP rocky planets versus the stellar radius of their host stars, where we can appreciate how the scaled orbital locations do not depend on the stellar spectral types. The horizontal line indicates the tidal disruption limit. Data: NASA Exoplanet Archive (24/03/2025).