The Spitzer Space Telescope, which was launched in 2003, spotted an eruption of dust around a young star — the probable result of a collision between large asteroids.
“We think two big asteroids crashed into each other, creating a huge cloud of grains the size of very fine sand, which are now smashing themselves into smithereens and slowly leaking away from the star," said lead author Huan Meng of the University of Arizona, Tucson, in an article published Friday online in the journal Science.
While Spitzer has observed suspected asteroid smash-ups before, this marks the first time scientists have been able to collect data before and after a planetary collision. The data will help researchers understand how rocky planets, like Earth, are created.
Rocky planets start life off as dusty material rotating around young stars. The material then bunches together to form asteroids that slam into each other.
Afterwards, and only in a few instances, do these smashed-up clumps grow and transform into small planets. In about 100 million years, the objects grow into terrestrial planets.
Astronomers at the University of Arizona wanted details of such a smash-up and decided to set the Spitzer's infrared eyes on the star NGC 2547-ID8, thought to be about 35 million years old. Starting in May 2012, the telescope began watching the star on a regular basis.
It took five months, but eventually Spitzer captured what researchers believe are asteroids ramming into each other.
"We not only witnessed what appears to be the wreckage of a huge smash-up, but have been able to track how it is changing — the signal is fading as the cloud destroys itself by grinding its grains down so they escape from the star," said Kate Su, A co-author of the study.
A thick cloud of dusty debris now orbits the star. Scientists are examining the undulations of infrared rays and dust levels, gathering unique data on how collisions become rocky planets.
"We are watching rocky planet formation happen right in front of us," said George Rieke, another co-author of the study. "This is a unique chance to study this process in near real-time."