VISTA finds 96 star clusters hidden behind dust in Milky Way

Washington, Aug 4 (ANI): Using data from the VISTA infrared survey telescope at ESO's Paranal Observatory, an international team of astronomers has discovered 96 new open clusters hidden by the dust in the Milky Way.

The result comes just one year after the start of the VISTA Variables in the Via Lactea programme (VVV) [1], one of the six public surveys on the new telescope.

"This discovery highlights the potential of VISTA and the VVV survey for finding star clusters, especially those hiding in dusty star-forming regions in the Milky Way's disc. VVV goes much deeper than other surveys," Jura Borissova, lead author of the study, said.

The majority of stars with more than half of the mass of our Sun form in groups, called open clusters. These clusters are the building blocks of galaxies and vital for the formation and evolution of galaxies such as our own.

However, stellar clusters form in very dusty regions that diffuse and absorb most of the visible light that the young stars emit, making them invisible to most sky surveys, but not to the 4.1-m infrared VISTA telescope.

"In order to trace the youngest star cluster formation, we concentrated our search towards known star-forming areas," Dante Minniti, lead scientist of the VVV survey, said.

"In regions that looked empty in previous visible-light surveys, the sensitive VISTA infrared detectors uncovered many new objects," Minniti added.

By using carefully tuned computer software, the team was able to remove the foreground stars appearing in front of each cluster in order to count the genuine cluster members.

"We found that most of the clusters are very small and only have about 10-20 stars," Radostin Kurtev, another member of the team, explained.

"Compared to typical open clusters, these are very faint and compact objects-the dust in front of these clusters makes them appear 10 000 to 100 million times fainter in visible light.

"It's no wonder they were hidden," Kurtev stated.

Furthermore, these new 96 open clusters could be only the tip of the iceberg.

"We've just started to use more sophisticated automatic software to search for less concentrated and older clusters. I am confident that many more are coming soon," Borissova added.

The results will appear in the journal Astronomy and Astrophysics. (ANI)