Astronomers discovered a group of young stars at the heart of the Milky Way, a region previously thought to consist of a mainly mature population. Astronomers claim that these stars form a disk that passes through the outer part of the Milky Way’s central bulge.
Astronomers led by Pontificia Universidad Católica de Chile (PUCC) discovered the disk when analyzing data collected between 2010 and 2014 at the Paranal Obervatory in Chile. “The central bulge of the Milky Way is thought to consist of vast numbers of old stars. But the VISTA data has revealed something new – and very young by astronomical standards!” Istvan Dékány of PUCC and lead author of the study said.
The entire group of stars has not been directly seen; however, its presence can be deduced by detecting a group of extremely odd and bright stars called Cepheids. While reviewing the data, researchers located 655 candidates that could be Cepheids, Nature World News reports.
Cepheids are stars that grow and contract periodically. Their cycles can last from a few days to a few months, and their level of brightness changes in the process. In other words, they change over time. Space.com calls them variable stars.
Cepheids come in both a younger and older class, and out of the 655, the astronomers discovered that 35 could fit into a sub-type category called classical Cepheids, the study’s release explained. This means that the stars are very young and appear much brighter than the older stars in the Milky Way’s central bulge.
A co-author on the study (and paper) Daniel Majaess of Saint Mary’s University in Nova Scotia, Canada, said in an email, “I couldn’t help think how amazed Henrietta Leavitt would be to learn about the important and diverse role Cepheids would play in shaping our understanding of the cosmos, all of which is invariably tied to her seminal discovery of the Cepheid period-luminosity relationship. From helping define the extragalactic distance scale and expansion rate of the universe, to now-seminal constraints on the nature of the mysterious region encompassing the galactic center.”
Dekany added that this new find is a “powerful demonstration of the recent technological advancement in infrared astronomy.” The data comes from the Vista Variables in the Vía Láctea Survey (VVV), completed by the European Southern Observatory’s VISTA telescope at the Paranal Observatory in Chile between 2010 and 2014.
VISTA’s “large field of view and superb near-infrared imaging capability allowed us to penetrate through the vast amount of interstellar dust that is blocking our view towards the inner Milky Way, and probe areas that are invisible in the optical light.”
The discovery of the younger stars demonstrates that new supplies of stars have continued to shine in the Milky Way’s central area for 100 million years.