Nickel and iron in the comet’s atmosphere
While watching with Very large telescope At the European Southern Observatory (ESO), researchers surprisingly found nickel and iron in the atmospheres of some comets. So far, traces of these elements have only been observed in tail stars which are very close to the Sun. Nickel is also found on the interstellar comet 2I / Borisov.
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Iron and nickel have been detected in the atmospheres of many comets such as C / 2016 R2 (PANSTARRS). images: ESO / L. Calada, SPECULOOS / E. Jehin, Manfroid et al. [Groansicht] |
“It was a big surprise for us to be able to detect iron and nickel atoms in the atmosphere of all the 20 or so comets that we have observed in the last two decades,” said Jean Manfred of the University of Liège in Belgium. From the present study is presented directed. These elements are found even in comets that are relatively far from the sun.
The researchers speculate that the comet will have elements such as iron and nickel. But it shouldn’t be detected in the thin atmosphere of comets over great distances, because the lower temperature there doesn’t actually change to its gaseous state, which is sublimation. Now, however, nickel and iron fumes have also been found in comets that are three times more distant from the Sun than Earth.
It is also interesting to know that the comet’s atmosphere contains equal amounts of nickel and iron. This is interesting because meteorites typically contain ten times more iron than nickel. “Comets formed about 4.6 billion years ago, in a very small solar system, and haven’t changed since then. In this sense, they are similar to astronomical fossils, ”explains Emmanuel Gehen of the University of Liège.
Belgian team together Very large telescope The European Southern Observatory (ESO) (VLT) observed many comets for nearly twenty years, but traces of nickel and iron ignored their spectroscopic investigations for a long time: “This discovery has been under the radar for many years,” said Gehen.
In the analysis of their data Spectrometer ultraviolet dan optics
From the VLT they ended up observing several unknown spectral lines, which upon closer inspection turned out to be indicators of neutral nickel and iron atoms. However, the percentages are small: the team estimates that there is only 1 gram of iron and nickel for every 100 kilograms of water in the comet’s atmosphere.
“Usually there is ten times more iron than nickel,” says Damien Hotsmaker of Lttich University. “However, in the comet’s atmosphere, we found roughly the same amount for the two elements.” “We found that it could have come from a special kind of material on the surface of the comet’s core that sublimes at a fairly low temperature, releasing iron and nickel in roughly equal proportions.”
The team is not yet able to determine what material might be in it, but hopes to carry out investigations in the future, including new telescopes such as telescopes. Very large telescope. In addition, evidence of iron and nickel can also be found in ancient monitoring data. “Now people will look for these lines in their archival data from other telescopes,” said Jihen. “We think this will also start new work on this topic.”
Clearly, heavier elements are not only found in the vicinity of the “real” comet: a Polish research team has successfully detected traces of nickel gas as well in the interstellar comet 2I / Borisov. This with Very large telescope It was investigated when it was about 300 million kilometers from the sun, about twice the distance between Earth and the sun. “At first we found it hard to believe that 2I / Borisov actually had nickel atoms far away from the sun. It took a lot of tests and examinations before we finally convinced ourselves, ”recalls Piotr Guzik of the Jagiellonian University in Krakow, Poland.
The two teams report their findings in two specialist articles now in the journal nature Appear.
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Manfroid, J., Hutsemkers, D. & Jehin, E. (2021): Iron and nickel atoms in comet atmospheres even far from the sun, Nature, 593, 372 (kein freie Version verfgbar) |
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