Asteroids found orbiting each other between Mars and Jupiter
A group of astronomers observed an intriguing and unusual object in the asteroid belt between Mars and Jupiter, with help from the NASA/ESA Hubble Space Telescope.
Two asteroids were seen orbiting each other and exhibiting features of comets - the bright coma and a long tail. The findings were published in Science journal 'Nature' on Wednesday.
"In September 2016, just before the asteroid 288P made its closest approach to the Sun, it was close enough to Earth to allow astronomers a detailed look at it using the NASA/ESA Hubble Space Telescope. The images of 288P, which is located in the asteroid belt between Mars and Jupiter, revealed that it was actually not a single object, but two asteroids of almost the same mass and size, orbiting each other at a distance of about 100 km. That discovery was in itself an important find; because they orbit each other, the masses of the objects in such systems can be measured," a website said.
288P is thus the first known binary asteroid. It is also classified as a "main-belt comet".
The main-belt comets are those that orbit amongst the numerous asteroids between Mars and Jupiter. Understanding the evolution of these, the website explains, would be crucial to understanding formation and evolution of the whole Solar System. Main-belt comets could throw light on how water came to Earth. Very few of this type of objects are known, so 288P "presents itself as an extremely important system for future studies," a daily reported.
Observing 288P could yield information about its past. Surface ice cannot survive in the asteroid belt for the age of the Solar System but can be protected for billions of years by a refractory dust mantle, only a few metres thick. The team estimates that 288P has existed as a binary system for only about 5,000 years. The most probable formation scenario of 288P is a breakup due to fast rotation. After that, the two fragments may have been moved further apart by sublimation torques.