John Hopton for redOrbit.com – Your Universe Online
From ancient, dying stars to our toothbrushes, the chemical element fluorine which is used in toothpaste was formed in stars of the same type as our sun billions of years ago, scientists from Lund University in Sweden believe.
The formation happens towards the end of a star’s life, a point at which they have expanded, are heavier and are referred to as a red giant. Various chemical elements are created within the high pressure and temperature conditions inside a star. During the red giant stage, the star sheds its outer parts and forms a planetary nebula. The fluorine that is thrown out mixes with the gas surrounding the stars, known as the interstellar medium. The interstellar medium forms new stars and planets, and continues to be enriched when the new stars die. The planets in our own solar system, as well as our own sun, were actually formed out of material from these dead stars.
The theory that the creation of fluorine, until now something of a mystery, happened in this way is one of three that have been put forward in the past. According to Nils Ryde, a reader in astronomy at Lund, the new research indicates that “fluorine in our toothpaste originates from the sun’s dead ancestors.” Working with doctoral student Henrik Jönsson and colleagues from Ireland and the US, Ryde looked at stars formed at various points in the history of the universe to ascertain if the amount of fluorine they contain fits with this theory.
Remarkably, the amount of different elements a star contains can be calculated by analyzing the light emitted it emits. This is due to the fact that light of a certain wavelength is indicative of a certain element. Light with a wavelength in the middle of the infrared spectrum, the area where the important signal is found in this case, was studied by the researchers using a telescope in Hawaii and a new kind of instrument that is sensitive to this aspect of light.
“Constructing instruments that can measure infrared light with high resolution is very complicated and they have only recently become available,” Ryde explained.
The team now intends to look at other types of stars too. One of the things they want to assess is whether fluorine could have been produced in the early universe, before the first red giants had formed. They will also study environments in the universe that are different from the environment surrounding the sun. For example, that which is close to the supermassive black hole at the center of the Milky Way, where the cycle of stars dying and new ones being born goes much faster than it does around the sun.
Ryde tells us that “By looking at the level of fluorine in the stars there, we can say whether the processes that form it are different.”