Dearth of near-Sun asteroids may be due to thermal forces

Los Angeles Times : Although asteroids can be found throughout the solar system, fewer than expected have been found within 10 solar diameters of the Sun, according to a new study published in Nature. Robert Jedicke, of the University of Hawaii Institute for Astronomy, and colleagues noticed the asteroid scarcity while working on a map of of near-Earth objects. They also found that asteroids near the Sun tend to have bright surfaces. Jedicke and his team propose that many asteroids in the region have succumbed to the Sun’s intense heat and radiation. Dark surfaces absorb more heat, which could trigger cracking or the explosion of volatile elements. Alternatively, solar radiation could speed up the asteroids’ rotation so much that the rocks break apart. Whatever the reason for the disappearing asteroids, the study could yield insight into their composition and internal structure.