Formation of intermediate-mass planets via magnetically controlled disk fragmentation

Intermediate-mass planets, from super-Earth to Neptune-sized bodies, are the most common types of planet in Galaxy1. The prevailing theory formation—core accretion2—predicts existence substantially fewer intermediate-mass giant planets than have been observed3,4. competing mechanism for formation—disk instability—can produce massive gas on wide orbits, such as HR 87995, by direct fragmentation protoplanetary disk6. Previously, magnetized disks has considered only when magneto-rotational instability is driving magnetic field growth7. However, this naturally superseded spiral-driven dynamo more realistic, non-ideal magneto-hydrodynamic conditions considered8,9. Here, we report simulations disk presence a dynamo. Fragmentation leads formation long-lived bound protoplanets with masses that at least one order magnitude smaller conventional models10,11. These light clumps survive shear and do not grow further owing shielding effect field, whereby pressure stifles local inflow matter. outcome population gaseous-rich intermediate masses, while giants found be rarer, qualitative agreement observed mass distribution exoplanets. type Galaxy, those between Earth Neptune, far clear. presented here, which incorporate dynamo, right longevity.