The atmospheres of comets in our solar system and beyond are unexpectedly high in iron and nickel, two research teams write in a scientific journal nature.
Belgian astronomers have discovered unexpected quantities of iron and nickel vapor in the atmosphere of about 20 comets in our solar system. Polish astronomers confirm that gaseous nickel is also present in the atmosphere of interstellar comet 2I / Borisov. The results came out on Wednesday Two Articles In the trade magazine nature.
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Mild spores
Belgian researchers led by Jean Manfred of the University of Liège made their discovery with the Europeans Very large telescope. And with that, they saw the specific colors of the light (spectral lines) belonging to iron and nickel. The team has been studying comets for twenty years, but they only recently discovered metallic gas, because it is very dilute. Researchers estimate that for every 100 kilograms of water in a comet’s atmosphere, there is only one gram of iron and roughly the same amount of nickel.
Lead researcher Manfred says that finding heavy elements such as iron and nickel in the effluents around comets is remarkable. In fact, you only expect water vapor there, because the mineral only becomes gaseous near the sun. “The discovery of iron and nickel atoms in the atmospheres of all 20 or so comets that we have observed over the past two decades was a huge surprise, even comets in cold space far from the sun.”
Surprising percentage
Not only is the discovery of the gaseous metal, but also the 50th ratio between iron and nickel is amazing, the astronomers wrote in their press release. Typically, materials in our solar system, such as those in the sun and meteorites, contain about ten times the amount of iron as nickel.
“We think these elements may come from a special type of material on the surface of the comet’s nucleus, which becomes gaseous at relatively low temperatures and releases an amount of iron such as nickel,” said study co-author Damien Hutsemékers from the University of Liège. .
Interstellar metallic vapor
Examining comets from our solar system gives astronomers a look back in time: “They formed about 4.6 billion years ago in the very young solar system, and they have not changed since.” Co-author Emmanuel Gehen, also from the University of Liège, says, “They are astronomical fossils. In a way. ”But are comets organized around other stars as they are around our sun?
In 2019, astronomers among thousands had the opportunity to answer this question when interstellar comet 2I / Borisov passed through our solar system. It moved too fast for the sun’s gravity to bear it, and it had to come from interstellar space. Research by Polish astronomers now shows that 2I / Borisov’s atmosphere also contains gaseous nickel.
Imagine: In other planetary systems there are comets that look like two drops of water to those in our solar system – how awesome is that? Says one of the discoverers of 2I / Borisov nickel pathways, Micha من Drahus of Jagiellonian University.
Follow-up research will be difficult, because 2I / Borisov is already racing outside our solar system at high speed. So comet researchers will have to primarily search archive data for traces of metal vapor.
Resources: ESO press releaseAnd the Nature: iron and nickel in comets NattosE: Nickel in an interstellar comet
Image: Traces of iron (blue spectral lines) and nickel (orange) in the atmosphere of comet C / 2016 R2. Source: ESO / L. Kalsada, SPECULOOS Group / E. Jehen, Manfred et al.