How does fluorine form in the universe? New discovery of galaxies 12 billion light-years away...

A new discovery reveals how fluorine, an element found in our bones and teeth in the form of fluoride, was formed in the universe. A team of astronomers using the Atacama Large Millimeter/Submillimeter Array (ALMA) detected this element in a very distant galaxy whose light took more than 12 billion years to reach us. This is the first time that fluorine has been detected in such a distant star-forming galaxy.

"We all know about fluoride because the toothpaste we use every day contains it in the form of fluoride," said Maximilien Franco from the University of Hertfordshire in the United Kingdom. He led the new study, published in Nature Astronomy on Nov. 4. Like most elements around us, fluorine is produced inside stars, but, until now, scientists have not known exactly how the element is produced. The researchers say, "We don't even know which types of stars produce most of the fluorine in the universe!"

Franco and his collaborators found fluorine (in the form of hydrogen fluoride) in a large gas cloud in the distant galaxy NGP-190387. Since stars expel the elements they form in their cores when they reach the end of their lives, this detection implies that the stars that create fluorine must undergo relatively short life cycles.

The team concluded that Wolf-Rayet stars, very large stars with lifetimes of only a few million years, are the most likely sites for fluorine production. They say they are needed to explain the amount of hydrogen fluoride the team found. Wolf-Rayet stars were previously considered a possible source of cosmic fluorine, but astronomers have not known until now how important they were in producing the element in the early universe.

"We have shown that Wolf-Rayet stars are among the most massive stars known to explode violently at the end of their lives, somehow helping to keep our teeth in good health!" Franco joked.

In addition to these stars, past research has suggested other scenarios for how fluoride is produced and expelled. One example includes the pulsation of giant evolved stars with masses several times that of our Sun, which are known as asymptotic giants. But the team believes that these scenarios, some of which take billions of years to occur, may not fully explain the amount of fluorine in NGP-190387.

"For this galaxy, it only took tens or hundreds of millions of years for fluorine levels to match those found in stars in the Milky Way, which is 13.5 billion years old. This is a completely unexpected result," said Chiaki Kobayashi, a professor at the University of Hertfordshire. "Our measurements add a whole new constraint to the origin of fluorine, which has been studied for 20 years."

The discovery of NGP-190387 marks the first discovery of fluorine outside the Milky Way and its neighboring galaxies. Astronomers have previously found the element in distant quasars, bright objects driven by supermassive black holes at the centers of some galaxies. But the element has never before been observed in star-forming galaxies so early in the history of the universe.

The team's detection of fluorine was a serendipitous discovery, thanks to the use of space and ground-based observatories. NGP-190387 was originally discovered by the European Space Agency's Herschel Space Observatory and later observed by ALMA in Chile, where it is very bright for its distance. data from ALMA confirm that the exceptional brightness of NGP-190387 is partly caused by another known It is located between NGP-190387 and Earth, very close to the line of sight. This massive galaxy amplifies the light observed by Franco and his collaborators, allowing them to detect the faint radiation emitted by fluorine in NGP-190387 billions of years ago.

Future studies of NGP-190387 with the Extremely Large Telescope (ELT) - ESO's new flagship project that is being built in Chile and will begin operating within a decade - may reveal further secrets about this galaxy. "ALMA is sensitive to radiation emitted by cold interstellar gas and dust," said Chentao Yang, an ESO researcher in Chile. "With ELT, we will be able to observe NGP-190387 through direct light from the star and obtain key information about the stellar content of this galaxy."