Heavy metal fumes in comets far from the sun

This is the first time that such heavy atoms, which are usually seen in hot environments, have been detected in the cold atmosphere of distant comets., Explains ESO in a press release.

The peaks in the spectrum belong to very specific elements, and those produced by iron and nickel are indicated by blue and orange dashes, respectively.

Photo: SO / L. Road, Team SPECULOOS / E. JEHEN, Manfroid et al.

It was a great surprise that iron and nickel atoms were discovered in the atmosphere of all comets that we have observed during the past two decades, about twenty of them, and even those far from the sun, in the cold. from spaceSaid Jan Manfred from the University of Liège in Belgium.

Astronomers have known that heavy metals are found in the dust and rocks of comet nuclei. However, they did not expect to find it in their atmosphere when they were further from the sun, as there are no minerals in solid form. Sublime In general it is not at low temperature (sublimation is the transition from a solid state to a gas state).

Nickel and iron fumes have been detected in comets that were observed more than 480 million kilometers from the sun, more than three times the distance between Earth and the sun.The statement continued.

Scientists have found that iron and nickel are present in roughly equal quantities in the atmosphere of all the observed comets. However, in the matter of the solar system, for example in the sun and meteors, one generally finds about ten times more iron than nickel.

So this new data will have ramifications On how astronomers understand the formation of comets and the solar system.

Comets […] They are like fossils for astronomersEmmanuel Gehen, study co-author and researcher at the University of Liège, explains.

The optical spectra of comets have been studied for decades, but no one has discovered the presence of nickel and iron in their atmosphere.

This discovery remained under the radar for many years.

To achieve this, the researchers used data from the ESO’s Visible and Ultraviolet Spectrophotometer, which analyzes the atmospheres of comets at various distances from the sun.

This technology allows astronomers to reveal the formation of stars: each chemical element, atom or molecule, leaves a unique imprint – a set of lines – in the light spectrum of observed objects., Explains ESO.

Scientists have detected faint, unknown lines in the spectrums of the spectrophotometer data. On closer inspection, they noticed thisThey indicated the existence of neutral atoms of iron and nickel.

Researchers estimate that for every 100 kilograms of water in comets’ atmosphere there is only 1 gram of iron and roughly the same amount of nickel.

Iron is usually ten times more abundant than nickel, and in the atmospheres of these comets we found roughly the same amount for both elements.Belgian authors explain this work, published in the journal nature (A new window) (In English).

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We came to the conclusion that it could come from a certain type of material on the surface of the comet nucleus, sublimate at a fairly low temperature and release iron and nickel in almost identical proportions.Damien Hatsemikers, who is also a member of the Liege University team, explains.

Mysterious nature

Currently, scientists do not yet know the exact nature of this substance, however Developments in Astronomy Instruments […] Researchers should be allowed to confirm (in the coming years) the source of the iron and nickel atoms in comets’ atmospheres.

Now others will look for these lines and those of other minerals in the data from many telescopes.Emmanuel Gehen explains.

We think this will lead to more work on this as well.

Interstellar heavy metals

A Polish team showed that heavy metals are also present in the atmosphere of interstellar comet 2I / Borisov, the first of its kind to visit our solar system.

Artist’s impression of Comet 2I / Borisov.

Photo: ESO / M. Cormiser

These minerals were observed with a VLT X-shooter ESO spectrometer during the passage of the comet’s perihelion about a year and a half ago, when it was about 300 million kilometers from the sun, or about twice the distance between the Earth and the sun. They discovered that 2I / Borisov atmosphere also contains gaseous nickel.

At first, we found it difficult to believe that atomic nickel could actually be present in the 2I / Borisov atmosphere far from the sun. It took a lot of testing and verification before we could convince ourselvesJagiellonian University, Piotr Guzik, explains.

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This result is surprising, because before the two studies published today, Gases containing heavy metal atoms are only observed in hot environments, for example, in the atmospheres of extremely hot exoplanets or vaporizing comets that have passed near the sun.

And we suddenly understood that nickel is present in comet atmospheres in other corners of the galaxy.Co-author Micha Drahus, who is also from Jagiellonian University, says.

Details of this second study are also published in the journal nature (A new window) (In English)

Polish and Belgian work show that comets of the Solar System 2I / Borisov have more in common than previously thought. Now imagine comets in our solar system have true analogues in other planetary systems: that’s really coolMikai Drahos concludes.