Study explains optical illusion at the center of the Milky Way

Scientists in Sweden think the mysterious presence of exotic elements at the center of the Milky Way isn't a mystery at all, but an optical illusion.

The elements aren't actually there, astronomers from Lund University argue in a new paper, published this week in the Astrophysical Journal.

Last year, scientists reported observations of high levels of scandium near the black hole at the center of our galaxy. Emissions from three red giant stars revealed the surprising spectrographic signatures of three exotic elements, according to the original study.

But when scientists at Lund, in collaboration with researchers at UCLA, reexamined the spectral data, they found evidence of a cosmic magic trick.

Because red giant stars feature relatively low temperatures, electrons behave differently. In other words, the spectral signature of scandium changes depending on its temperature.

"These giant red stars have used up most of their hydrogen fuel and their temperatures are therefore only half of the sun's," Brian Thorsbro, a doctoral student in astronomy at Lund University, said in a news release.

Thorsbro and his research partners hope their findings will improve elemental mapping efforts.

Astronomers at Lund and UCLA are currently using the W. M. Keck Observatory, the world's largest telescope, located in Hawaii, to document the elements in stars throughout the center of the Milky Way.

"Our research collaboration is world-leading in terms of systematically mapping the elements contained in the huge central star cluster -- the star cluster that surrounds the black hole," said Nils Ryde, astronomer at Lund University.

To identify different elements, scientists study the spectral patterns of near-infrared light, which includes thermal radiation. Near-infrared light penetrates dust, allowing scientists to accurately measure it from several million light-years away. But near-infrared light is also affected by temperature, which can interfere with scientists' ability to accurately measure elemental concentrations.

Before astronomers can report abundances of scandium, authors of the new study argue researchers must consider alternative explanations for the unusual spectral lines.

"We argue that the strong lines are a property of the line formation process that currently escapes accurate theoretical modeling," researchers wrote in their paper.

Related Links
Stellar Chemistry, The Universe And All Within It

Tweet

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only

SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Gaia detects a shake in the Milky Way
Barcelona, Spain (SPX) Sep 25, 2018
"We have observed shapes with different morphologies, such as a spiral similar to a snail's shell. The existence of these substructures has been observed for the first time thanks to the unprecedented precision of the data brought by Gaia satellite, from the European Space Agency (ESA)", says Teresa Antoja, researcher at ICCUB (IEEC-UB) and first signer of the article. "These substructures -she adds- allow us to conclude that the disk of our galaxy suffered an important gravitational disturbance a ... read more