Curcumbinary planets — such as Kepler-34(AB)b — very likely form relatively far away from their parent stars, before migrating in closer, according to new research from the University of Bristol.
The new research, focused on Kepler-34(AB)b, explores the formative process of planets in circumbinary star-systems — and was performed with the aid of the Kepler space telescope.
The University of Bristol provides more:
There are few environments more extreme than a binary star system in which planet formation can occur. Powerful gravitational perturbations from the two stars on the rocky building blocks of planets lead to destructive collisions that grind down the material. So, how can the presence of such planets be explained?
In research published this week in Astrophysical Journal Letters, Dr Zoe Leinhardt and colleagues from Bristol’s School of Physics have completed computer simulations of the early stages of planet formation around the binary stars using a sophisticated model that calculates the effect of gravity and physical collisions on and between one million planetary building blocks. They found that the majority of these planets must have formed much further away from the central binary stars and then migrated to their current location.
Dr Leinhardt stated: “Our simulations show that the circumbinary disk is a hostile environment even for large, gravitationally strong objects. Taking into account data on collisions as well as the physical growth rate of planets, we found that Kepler 34(AB)b would have struggled to grow where we find it now.”
With these things in mind, it seems rather likely that “all of the currently known circumbinary planets have also migrated significantly from their formation locations — with the possible exception of Kepler-47 (AB)c which is further away from the binary stars than any of the other circumbinary planets.”
Stefan Lines, the lead-author of the new study, noted: “Circumbinary planets have captured the imagination of many science-fiction writers and film-makers — our research shows just how remarkable such planets are. Understanding more about where they form will assist future exoplanet discovery missions in the hunt for earth-like planets in binary star systems.”