A short-period censor of Sub-Jupiter mass exoplanets with low density.
SZABO GY.M. and KISS L.L.
Abstract (from CDS):
Despite the existence of many short-period hot Jupiters, there is not one hot Neptune with an orbital period less than 2.5 days. Here, we discuss a cluster analysis of the currently known 106 transiting exoplanets to investigate a possible explanation for this observation. We find two distinct clusters in the mass-density space, one with hot Jupiters with a wide range of orbital periods (0.8-114 days) and a narrow range of planet radii (1.2±0.2 RJ ) and another one with a mixture of super-Earths, hot Neptunes, and hot Jupiters, exhibiting a surprisingly narrow period distribution (3.7±0.8 days). These two clusters follow strikingly different distributions in the period-radius parameter plane. The branch of sub-Jupiter mass exoplanets is censored by the orbital period at the large-radius end: no planets with mass between 0.02 and 0.8 MJ or with radius between 0.25 and 1.0 RJare known with Porb< 2.5 days. This clustering is not predicted by current theories of planet formation and evolution, which we also review briefly.
planets and satellites: general