According to new research, many planetary systems can be wiped out before they even have a chance to form. The culprit: nearby stars that are capable of vaporizing entire protoplanetary disks as soon as they begin to form.
Stars tend to clusters as single giant nebula fragments into many smaller pieces. Of course, some stars form first. Under these stars will be big, hot ones that can pump out tons of intense high-energy radiation.
And where does all this radiation go? Straight into the gas and dust disks that swirl around neighboring, less developed stars.
Francisca Concha-Ramírez, a PhD student at the University of Leiden, conducted research using a large number of computer simulations of newly emerging planetary systems. The simulations took into account the complicating effects of radiation from nearby stars.
They found that when neighboring stars are too close, the radiation from these stars blows dust away from young protoplanetary systems. This robs these systems of the vital building blocks for building planets and potentially robs these stars of the planetary systems.
Concha-Ramírez then compared their simulations with observations of nearby star-forming regions such as the Orion Nebula. “Our simulations agreed with the observations. We have seen that disks with many neighboring stars are lighter than disks with few neighboring stars. The radiation from stars evaporates the dust in the disks in a process we call photoevaporation. Photoevaporation is the main cause of disc weight loss. “
The results suggest that in order for a protoplanetary disk to survive, it must move away from its neighbors. One way to do this is through a collision that may have occurred in the early days of our own solar system.
“There may have been a collision between our circumstellar disk and another disk,” says Concha-Ramírez. “We can see evidence of this on the edge of our solar system in the region of the planet Neptune. Suddenly there are far fewer asteroids here, suggesting that another disk may have snapped up material. And there is another interesting indication that a disk collision may have occurred: asteroids orbiting the sun on a different plane with respect to the earth. These asteroids are likely from another disk. “