Asteroid Odd Couple: Spitting Space-Rock Duo Is Truly Bizarre – Space.com
In the asteroid belt between Mars and Jupiter, scientists have discovered a pair of space rocks, collectively called 288P, that don’t behave like anything previously observed in that region. The rocks’ strange characteristics could provide new clues about the formation of planets in the solar system, the scientists said.
The two asteroids, collectively known as 288P, are locked in orbit around each other and are also spewing water vapor into space like comets (which originate in the region beyond Neptune). Many asteroids between Jupiter and Mars can claim one of those characteristics (orbiting one another or releasing vapor), but this is the first time that researchers have identified an object with both features, the researchers said.
“The uniqueness of 288P is the combination [of factors],” Jessica Agarwal, lead author of a paper describing the new research, told Space.com. [The Strangest Asteroids in the Solar System]
Credit: NASA, ESA, and J. Agarwal (Max Planck Institute for Solar System Research)
And 288P’s exclusive mix of traits doesn’t end there.
The peculiar rocks were initially identified as a single object, but follow-up observations by Agarwal and her team revealed that 288P consists of two asteroids, each about 1 kilometer (0.62 miles) wide, locked in orbit. Once again, there are many main-belt asteroids in that size group, but the team also discovered that the two rocks are orbiting much, much farther apart than other asteroids of that size typically do.
The asteroids in 288P orbit each other at a distance of about 100 km (about 62 miles), or at least 10 times farther apart than models predict they should be, said Agarwal, who is a researcher at the Max Planck Institute for Solar System Research in Germany. The rocks’ orbits are also highly eccentric (meaning very elongated, rather than closer to a perfect circle), another unique characteristic for two bodies with the size and separation of 288P, Argawal said. The combination of orbital characteristics found with 288P is “different from all other known [asteroid] binaries,” she said.
The evolution of asteroids
Why is 288P’s unique mix of traits interesting to researchers?
Objects in the asteroid belt have remained almost completely unchanged since the formation of the planets. Therefore, things like asteroid composition provide clues about the material thate formed the planets. Understanding the processes that shape and change those rocks can help scientists piece together the story of how planets formed, and other major questions like why some planets (like Earth) have plentiful amounts of water, while others do not.