SIMBAD references

Using the period and mass data of 279 extrasolar planets, we have constructed a coupled period-mass function through a nonparametric approach. This analytic expression of the coupled period-mass function has been obtained for the first time in this field. Moreover, due to a moderate period-mass correlation, the shapes of mass/period functions vary as a function of period/mass. These results of mass and period functions give way to two important implications: (1) the deficit of massive close-in planets is confirmed, and (2) the more massive planets have larger ranges of possible semimajor axes. These interesting statistical results will provide important clues to the theories of planetary formation.