0203 GMT May 26, 2019
The two space rocks, located in the asteroid belt between Mars and Jupiter, are collectively known as 288P and represent the first known binary asteroid which is also classified as a main-belt comet, according to express.co.uk.
Comet-like features exhibited by the binary asteroid include a bright halo of material and a long tail of dust, scientists discovered.
The two asteroids of almost the same mass and size were orbiting each other at a distance of 96km when discovered.
Jessica Agarwal of the Max Planck Institute for Solar System Research, explained, “We detected strong indications of the sublimation of water ice due to the increased solar heating — similar to how the tail of a comet is created.”
She also noted how the observed activity of 288P also reveals information about its past.
Agarwal, who led the study, said: “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 meters thick.”
Due to this, the team of researchers has concluded that 288P has existed as a binary system for roughly 5,000 years.
Certain features of 288P — such as wide separation of the two components, near-equal component size, high eccentricity and comet-like activity — make it unique among the few known wide asteroid binaries in the solar system.
The fact 288P is vastly different from all other known binary asteroids raises questions about whether it is not just a coincidence that it has such unique properties.
Agarwal added, “We need more theoretical and observational work, as well as more objects similar to 288P, to find an answer to this question.”
Understanding the origin and evolution of main-belt comets is crucial to our understanding of the formation and evolution of the whole Solar System.
Further understanding main-belt comets may, for example, help to answer how water came to Earth.
Because of the fact that only a few objects of this type are known, 288P represents an important system for future studies.
Asteroids are difficult for researchers to study, simply because these space rocks are very small and very dim.
The research was presented in a paper published in the journal Nature.