As with the sibling post, I'd also wonder if it's because of the failures that Kepler has had. Right now it can only point at a really small part of the sky an

As with the sibling post, I'd also wonder if it's because of the failures that Kepler has had. Right now it can only point at a really small part of the sky and it's possible that that star forming region just happened to form mostly smaller planets. Horrible armchair speculation: the graph ALMOST looks like there's two bell curves summed together. a larger planet forming one and a smaller planet forming one, might indicate that there's some threshold for making larger planets that has to be crossed first.