"Our results show that the final distribution of planets does not vary smoothly with distance from the star, but instead has clear ‘deserts' - deficits of planets - and ‘pile-ups' of planets at particular locations," said Ilaria Pascucci, an assistant professor at the University of Arizona's Lunar and Planetary Laboratory, who presented the results at the Lunar and Planetary Science Conference in The Woodlands, Texas on March 19.
So how are these "deserts" and "pile-ups" formed?
After a young star is born, it is surrounded by a rotating cloud. Over time, this cloud flattens out and forms a protoplanetary disk - eventually planets will grow here. However, before this happens, a tug-o-war ensues within the protoplanetary gas and dust.
The young star feeds off the protoplanetary disk, gaining mass - this mass generates a dominant gravitational field pulling more material star-wards. At the same time, the star is pumping out powerful radiation that pushes the protoplanetary disk away, effectively "putting the breaks" on the gas and dust from falling into the star. At a certain point, the inward gravitational pull balances with the outward radiation pressure, clearing a zone around the star.