A team of astronomers believes they have solved a mystery involving asteroids that disappeared for no other reason than coming within a certain distance of the sun.

Published in the journal Nature, the new study examined why groups of asteroids closest to the sun were lacking in number while those farther out seemed to have just as many as expected.

"The discovery that asteroids must be breaking up when they approach too close to the Sun was surprising and that's why we spent so much time verifying our calculations," study co-author Dr. Robert Jedicke, a team member at the University of Hawai'i Institute for Astronomy, said in a press release.

According to The Los Angeles Times, the astronomers first noticed the missing asteroids only a few years ago. Rather than set to find them, the researchers wanted a better method for detecting what are known as Near-Earth Objects, most of which come from the asteroid belt between Mars and Jupiter.

Even with the new model, the astronomers were not able to explain what was going on with the asteroids closest to the sun. They concluded the asteroids are most likely cracking and breaking when they get too close.

"Perhaps the most intriguing outcome of this study is that it is now possible to test models of asteroid interiors simply by keeping track of their orbits and sizes," study lead author Mikael Granvik, a research scientist at the University of Helsinki, said in the release. "This is truly remarkable and was completely unexpected when we first started constructing the new NEO model."