TOI-1416 radial velocities

The position of TOI-1416 b within the radius-period distribution corroborates the idea that planets with periods of less than one day do not form any special group. It instead implies that ultra-short-period planets belong to a continuous distribution of super-Earth-like planets with periods ranging from the shortest known ones up to =~30 days; their period-radius distribution is delimited against larger radii by the Neptune Desert and by the period-radius valley that separates super-Earths from sub-Neptune planets.

In the abundance of small, short-periodic planets, a notable plateau has emerged between periods of 0.6-1.4 days, which is compatible with the low-eccentricity formation channel. For the Neptune Desert, its lower limits required a revision due to the increasing population of short-period planets; for periods shorter then 2 days, we establish a radius of 1.6R_{Earth}_ and a mass of 0.028M_jup_ (corresponding to 8.9M_{Earth}_) as the desert's lower limits.

We also provide corresponding limits to the Neptune Desert against the planets' insolation and effective temperatures.