With the help of the NASA / ESA Hubble Space Telescope, a group of scientists led by German astronomers has observed a strange type of object in the asteroid belt between Mars and Jupiter: these are two asteroids that orbit each other and exhibit similar characteristics. to a comet , including a bright coma and a long tail. It is the first known binary asteroid to be classified as a comet in the main asteroid belt.
The asteroid pair, named 288P, was observed in September 2016 just before the asteroid made its closest approach to the Sun. Astronomers saw that the object they were gazing at was not one, but two asteroids revolving around each other leaving a stream of dust in its wake. These types of asteroids that behave like a comet are not new, but they are not common either. What makes this discovery special is that it is a binary asteroid system: each asteroid – which also has almost the same mass and the same size – orbits the other at a distance of less than 100 kilometers . That discovery was itself an important find; since, because they orbit each other, the masses of objects in such systems can be measured.
Precisely when this pair of asteroids made its closest approach to the Sun, NASA took advantage of Hubble’s capabilities to capture clearer images of its nucleus and tail, also confirming the signature of a comet. Hence, this find is so special and unique.
“We detected strong indications for the sublimation of water ice due to the increase in solar temperature, similar to when the tail of a comet is created,” comments Jessica Agarwal of the Max Planck Institute and co-author of the work published in the journal Nature.
Researchers believe that 2006 VW139 (name given to the binary object first detected in 2006 as part of the Spacewatch asteroid search program) broke apart about 5,000 years ago under the stress of rotation , where the stream of vapor coming out of the fragments helped push them farther and farther;
Is it a unique object or will there be more of this type?
288P is very different from all the other binary asteroids that we know of, which raises a whole range of questions about its existence and the possibility of finding more objects similar to it. “ We need more theoretical and observational work, as well as more 288P-like objects, to find an answer to this question, “ says Agarwal.
Understanding how comets in the main asteroid belt orbiting between Mars and Jupiter formed and evolved is vital to further deepen our understanding of the formation and evolution of the entire Solar System and could answer such relevant questions as how water came to be. the earth. This strange hybrid is presented as an extremely important system for future studies.
Undoubtedly another item on Hubble’s list of unusual and exciting discoveries.
Reference: A binary main belt comet, Jessica Agarwal, David Jewitt, Max Mutchler, Harold Weaver, Stephen Larson. Nature 2017 spacetelescope.org/static/archives/releases/science_papers/heic1715/heic1715a.pdf
Image credit: ESA / Hubble, L. Calçada.
This set of images from the ESA / NASA Hubble Telescope reveals two asteroids orbiting each other with a bright halo (coma), and a long tail of dust.
