January 23, 2021

Solving a mystery in the center of the galaxy: an optical illusion – The Province

Solving a mystery in the center of the galaxy: an optical illusion - The Province

The high levels of scandium, vanadium or yttrium discovered last spring near the giant black hole of our galaxy they were in fact an optical illusion.

It is the explanation given now by astronomers of the University of Lund, in Sweden, to a previous study on the apparent presence of amazing and dramatically high levels of three different elements in giant red stars, located less than three light-years from the great black hole in the center of our galaxy.

Several possible explanations were presented, for example, that the high levels were the result of the disappearance of previous stars when falling in the black hole, or the result of the waste of the collisions of stars of neutrons.

Now, a group of astronomers from the University of Lund, among others, in collaboration with UCLA in California, have found an explanation for the high levels of scandium, vanadium and yttrium. They argue that the so-called spectral lines presented last spring were actually an optical illusion. The spectral lines are used to discover what elements a star contains, using its own light.

"These giant red stars they have consumed most of their hydrogen fuel and its temperatures are, therefore, only half of those of the Sun, "says Brian Thorsbro, the study's lead author and a doctoral student in astronomy at the University of Lund, in a statement.

According to the new study, the lowest temperatures of the giant stars helped create the optical illusion that appeared in the measurements of the spectral lines. Specifically, it means that the electrons in the elements behave differently at different temperatures, which in turn can be deceptive when measuring the spectral lines of elements in different stars. The conclusion is the result of close collaboration between astronomers and atomic physicists.

Brian Thorsbro and his colleagues have had the largest telescope in the world, at the W. M. Keck Observatory in Mauna Kea, Hawaii, at your disposal, thanks to your collaboration with R. Michael Rich at UCLA.

Using this telescope and others, the research team is conducting a complete mapping of the central areas of the Milky Way, exploring the spectral lines in the light of different stars to discover what elements they contain. The purpose is to gain an understanding of the events that have occurred in the history of the Milky Way, but also to understand how galaxies have been formed in general.


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