A baker adds more sugar to the dough, and the pie turns out different. So it is with a star: the composition of its "dough"—the cloud of gas and dust from which planets are born — determines what worlds will form around it. Astronomers have noticed that if a star has noticeably more carbon than oxygen, its giant planets tend to orbit at large distances, like the leisurely outer planets such as our Jupiter.
The scientists analyzed the spectra of 598 stars hosting 929 planets, gathered from three major sky surveys. They found that stars with a high carbon-to-oxygen ratio (C/O) prefer long orbits for their giants — years, not days. Models show that in such disks, more solid material accumulates in the outer regions, where large planets grow, only slightly migrating inward.
This discovery links the chemistry of the stellar disk to the architecture of distant worlds. Now, by looking at a star, one can predict in advance where to find its giant planets, and how they got there.
Our Sun has a C/O of about 0.5, and Jupiter orbits with a period of 12 years — right in line with the found pattern.
In Stanislaw Lem's novel "Solaris," an ocean planet orbits a binary star, and its strange chemistry gives rise to an unusual world, just as the new data link stellar composition to planets.