For the first time, astronomers have discovered iron and titanium in the atmosphere of a planet outside the solar system

This is, for example, like a red-hot exoplanet for about 620 light years, as astronomers say, "ultra-hot Jupiter." KELT-9b is a gigantic giant, like Jupiter in our system, but much larger – three times massive and twice larger than Jupiter – and rotates very close to the CELT-9 stars.

The "Ultra Hot Jupiter" is an unofficial name for exuplanets of the hot jupiter type with temperatures above 1700 ° C. They are so hot that they look a bit like the stars, even though the planets are ", Kevin Heng explains, astrophysicist at the University of Bern in Switzerland, who explored The temperature of KELT-9b can reach 4300 ° C.

By such a record heat, astronomers have succeeded in detecting Iron Titanium in the atmosphere of KELT-9b. Although researchers have long suspected that these elements should be in some exoplanets – iron is one of the most common elements in the universe – it is difficult to detect it in a cooler environment because atoms tend to "catch other molecules" said Heng. KELT-9b, however, is so hot that it does not condense in its atmosphere, and individual iron and other metal atoms fly one by one.

In the atmosphere of exoplanets, titanium has been observed before, but not atomic forms. In September 2017, astronomers discovered titanium dioxide in the atmosphere of an exoplanet Kepler-13A in a Hubble space telescope.

Different elements can be determined from the spectrum of light emitting objects. Because the exoplanets do not light their light, Heng and his team of researchers have studied the telescope data collected during the transition of the planet through the disk of the star.

Hengui and co-authors decided to carry out the study, these data are already easily collected. For colleagues from the University of Geneva who use spectral data to search for hydrogen in the KELT-9b atmosphere, "they stored the data in a drawer because there was no reason to search for iron or titanium" said Heng. – And then, a few months ago, we conducted a theoretical study that predicted the existence of iron and titanium in the atmosphere, which was motivated by searches. "

Using the centuries-old data from the Galileo National Telescope on La Palma, Spain, the researchers began searching for metals within 4 hours of the transit of KELT-9b in the light of the planet's atmosphere. This data was collected using the HARPS (High Accuracy Radial Velocity Planet Searcher) spectrographic instrument.

"Different atoms or molecules in the light spectrum only leave the traces that are characteristic of them," said Heng. "If the resolution is sufficient and the data is good, each molecule leaves a unique fingerprint." In order to detect iron or titanium prints, Hengas and his team suspected that they should be in the atmosphere of KELT-9b, "the use of high-quality computer knowledge, the availability of spectroscopic databases, processing and extra attention to detail," wrote Hengas on & # 39; s blog.

Heng & # 39; s team of help turned to Simon Grimm, an astrophysicist at the University of Bern, "who is an expert in calculating absorption lines for atoms and molecules," Heng wrote. "It is not easy to count because the power and shape of the millions and billions of spectrum lines must be measured."

Earlier KLET-9b atmospheric hydrogen studies found a strong hydrogen absorption line and without the complex analysis of the correlation, which Hengui and his team had to perform in search of iron and titanium. When astronomers were searching for hydrogen research, "there was a lack of theoretical motivation to seriously search for metals such as iron," Heng wrote.

Another study published in the journal Nature Astronomy on July 2 showed that hydrogen from the atmosphere of KELT-9b "bursts" and is drawn by a star. "It may be that the same happens with heavy metal elements (ie, heavier than hydrogen – value past.)

while it escapes dramatically, hydrogen can then "stretch" and heavier elements in the atmosphere ", – wrote Fei Yan, an astronomer of the Max Planck Institute of Astronomy and author of the main research.

Although the discovery of iron and titanium in the atmosphere of KELT-9b in itself was a huge discovery, Heng said that "the technology itself is truly amazing". "We will use the same technique for biology traces, or biomarkers," said Heng. "On Earth, we think it's oxygen and a few other hard-to-find molecules, but what are bio-significants in common – we do not know … If you know this, … you can use exactly the same technique to put these molecules on cooler, smaller planets. & # 39;

Almost astronomers will find no signs of life on this infernal planet, but Heng and KELT-9b have discovered other interesting elements. "I do not want to reveal too much, but we've found other metals," he said. – We also try to get the time from the Hubble Space Telescope and use it for water research. "The ultimate goal is a thorough chemical inventory of the planet." Hubble will also be able to provide knowledge of the KELT-9b air. "This violent storm should strike on this planet," he said.

The research was published on 15 August in Nature magazine.

Hanneke Weitering

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