Right-Sized Asteroid Belts Responsive to Life: Study

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According to a conducted study by Rebecca Martin, a NASA Sagan Fellow at University of Colorado in Boulder, together with astronomer Mario Livio of Space Telescope Science Institute in Baltimore, the existence of right-sized asteroid belts on solar systems with life-bearing planets could possibly boost up the birth and evolution of complex life.

Astronomy.com reports that the study suggests "size and location of an asteroid belt, shaped by the evolution of the Sun's protoplanetary disk and by the gravitational influence of a nearby giant Jupiter-like planet, may determine whether complex life will evolve on an Earth-like planet."

Their conclusion was based on thorough investigation of theoretical models and archival remarks of extra-solar Jupiter-sized planets and debris disks around young stars. "Our study shows that only a tiny fraction of planetary systems observed to date seem to have giant planets in the right location to produce an asteroid belt of the appropriate size, offering the potential for life on a nearby rocky planet," Martin, the study's lead author, declared.

Also, Martin and Livio implied that the position of an asteroid belt comparative to a Jupiter-like planet is not an accident. The asteroid belt in our solar system located between Mars and Jupiter is a section of millions of space rocks that are situated near the "snow line" which marks the border of a cold region where unsteady material such as water ice are far enough from the Sun to remain intact.

"To have such ideal conditions, you need a giant planet like Jupiter that is just outside the asteroid belt and that migrated a little bit, but not through the belt," Livio explained. "If a large planet like Jupiter migrates through the belt, it would scatter the material. If, on the other hand, a large planet did not migrate at all, that, too, is not good because the asteroid belt would be too massive. There would be so much bombardment from asteroids that life may never evolve."

After taking a look at all of the accessible space-based infrared interpretations of 90 stars having warm dust from NASA's Spitzer Space Telescope, indication showed the existence of an asteroid belt-like structure.   "The warm dust falls right onto our calculated snow lines, so the observations are consistent with our predictions," Martin shared.

Furthermore, Martin and Livio examined observations of the 520 huge planets discovered outside of our solar system. Only 19 were recorded to exist outside the snow line. With that, the study suggested that most of these huge planets that possibly formed outside the snow line have migrated too far inward to preserve the kind of slightly dispersed asteroid belt needed to foster enhanced evolution of life on an Earth-like planet near the belt. "Based on our scenario, we should concentrate our efforts to look for complex life in systems that have a giant planet outside of the snow line," Livio said.

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