Comets are comets, and asteroids are asteroids…except when they aren’t. Some asteroids appear to be active, and form the familiar comas, and even tails, of their comet cousins. Astronomers know only a few dozen examples of these active asteroids, but they suspect there are many more—and you can join the hunt. The asteroids you spot can reveal secrets about the history of the solar system.
asteroids Relatively simple. The remaining parts of the stillborn rocky planets, they are rich in carbon, iron and other heavier elements. They are basically just big balls of rock.
cometsHowever, it is more active. It’s a mixed bag of ice and lighter ores that formed at the outer edges of the Solar System during its infancy. Because of their lighter elements, when comets get very close to the sunbecomes turbulent, with light elements sublimating from the surface to form a coma, and sometimes even a gas tail that can extend for millions of miles.
So asteroids and comets are completely different. But in 1950, astronomers found the first signs of activity around an unexpected place. They discovered that the asteroid (4015) Wilson-Harrington is in a coma, just like a comet. But the body was definitely not guilty. It was definitely an asteroid, given that it was mostly made of a rocky formation.
In the past 70 years, astronomers have identified fewer than 30 active asteroids, and they still represent a great mystery to our understanding of the evolution of Solar System. So how did these little rocky bodies get enough of the light elements to form a coma or a tail?
Here comes the centaur
Active asteroids tell us something important about the history of the solar system. For example, one of the main outstanding puzzles in the evolution of planets is How did the earth get its water?. Our planet originally formed with a lot of water, but most of it either boiled off when the Earth’s surface was melting or trapped deep within the mantle. Getting water on the planet’s surface requires some kind of delivery system. Comets are one of the obvious vehicles, but there may not have been enough of them to roam the inner solar system to do the job.
Active asteroids may have done the enrichment a landbut we have so few examples in the modern solar system that it’s hard to identify.
Fortunately, these active asteroids are not alone. There is another distinct group of small bodies that inhabit the solar system: the centaurs. These asteroid-like bodies are located between orbits Jupiter And the Neptune. Astronomers believe that centaurs were once members of Kuiper belta ring of small objects outside the orbit of Neptune, wandered very close and were captured by gravity of the giant planets.
Centaurs themselves share characteristics with both asteroids and comets, and form a kind of hybrid population. Fewer than 20 of them produce a visible coma just like comets. This is particularly puzzling, because many of these active centaurs spend most of their time outside of Jupiter’s orbit, where it must be too cold for any frozen light elements to sublimate.
Astronomers need your help
This small but unique collection of asteroids and centaurs presents astronomers with many mysteries. For example, how are centaurs active despite being far from the sun? What do these energetic objects tell us about the history of the elements of light during The formation of the solar system?
To answer these questions, we need more data. Sure, there are more active asteroids, but they’re hard to spot. Not only are the asteroids relatively small, faint, and far from the sun, but the signs of their activity are very faint. Searching asteroid image catalogs takes special time and attention, looking for signs of a coma or a tail.
This is certainly a task beyond the capabilities of even the most complex automated algorithms – which means it is up to us to find new active asteroids.
paper Recently published in the prepress database arXiv Discusses a new scientific project to search for active asteroids. The project takes pictures of asteroids from the Dark Energy Survey (DES). Although the DES telescope was not designed to search for asteroids, its imaging capabilities make it an ideal asteroid finder.
However, to find more active asteroids, someone needs to look at the images and determine if there is any sign of activity. And here comes your turn: you simply visit Activeasteroids.net and click to start. After a brief tutorial, you can start flipping between images of asteroids and decide if you think they are active or not.
do not worry; as much astronomy Do not rest completely on your shoulders. Your answers will be compared to others before passing them on to the researchers.
With a larger catalog of known active asteroids, astronomers hope to begin characterizing and studying these objects in more detail. From there, they can begin to understand what these active asteroids might tell us about the history of the solar system.