Scientists found iron and nickel, which they described as a “big surprise”, inside the objects. Comets have been found throughout our solar system as well as in 2I / Borisov – an interstellar object that began life in another planetary system.
Such heavy metals are generally expected in warm environments and this is the first time they have been discovered in much colder atmospheres, the researchers say.
“It was a great surprise to detect iron and nickel atoms in the atmosphere of all the comets that we have observed in the past two decades, about 20 of them, and even in those far from the sun in the world. ‘cold space environment,’ said Jean Manfroid of the University of Liège, who led the study.
And the fact that they were found in objects that originate from such different parts of the universe suggests that there is an unknown affinity between our solar system and the distant atmospheric comet 2I / Borisov formed.
“If we can disentangle the origin of nickel and iron in regular comets and this interstellar object, we could uncover a common history of organic chemistry between different planetary systems,” scientists distant from the study wrote in an article by ‘accompaniment, published in Nature. They call the similarity between the two objects “striking”, especially given the unknown nature of 2I / Borisov and his distant birthplace.
Comets can offer glimpses of solar systems in much older states, as they have been made up of dust and ice from the time the planets first formed. Researchers are able to explore them by looking at their coma – the trail that follows the comet – and deducing their composition.
Usually metals are noticeably absent among these comas because the temperatures are not high enough.
Researchers who examined 2l / Borisov found that it appeared to emit nickel despite its distance from our sun. Rather than being released by heat, the metal can be released by photons, they suggest.
Researchers now want to know where these unexpected substances come from. But the comets themselves offer early clues.
Metals appear to be present in a particularly volatile state, for example, and the nickel / iron ratio is much higher than it usually is when looking at our sun or other meteoroids.
The two studies – one examining the interstellar comet and the other looking at objects in our solar system – are both published in Nature.