Astronomers Catalogue 84 Million Stars
October 24, 2012

Milky Way Stars Catalogued In Greatest Numbers Yet – 84 Million And Counting

[ Watch the Video: Gigapixel View Of Milky Way ]

Lee Rannals for - Your Universe Online

The European Southern Observatory (ESO) announced this morning that a team of astronomers have catalogued over 84 million stars in the central parts of the Milky Way.

This dataset contains more than ten times more stars than previous studies, and is a major step forward for understanding our galaxy.

“By observing in detail the myriads of stars surrounding the center of the Milky Way we can learn a lot more about the formation and evolution of not only our galaxy, but also spiral galaxies in general,” said Roberto Saito, lead author of the study published in the journal Astronomy & Astrophysics.

Understanding the formation and evolution of the Milky Way's bulge is vital for understanding the galaxy as a whole, according to ESO.

“Observations of the bulge of the Milky Way are very hard because it is obscured by dust,” said Dante Minniti, co-author of the study. “To peer into the heart of the galaxy, we need to observe in infrared light, which is less affected by the dust.”

ESO's 13.4-feet Visible and Infrared Survey Telescope for Astronomy (VISTA) enables astronomers to get a wide view with plenty of infrared detectors.

The astronomers are using data from the VISTA Variables in the Via Lactea program (VVV), which is one of six public surveys carried out with VISTA.

The team has used these data to compile the largest catalogue of the central concentration of stars in the Milky Way ever created.

In order to help analyze the catalogue, the brightness of each star is plotted against its color for about 84 million stars to create a color-magnitude diagram.

This plot contains more than ten times more stars than any previous study and is the first time it has been done for the entire bulge.

Color-magnitude diagrams are valuable tools that can be used by astronomers to study the different physical properties of stars, such as their temperatures, masses and ages.

“Each star occupies a particular spot in this diagram at any moment during its lifetime. Where it falls depends on how bright it is and how hot it is. Since the new data gives us a snapshot of all the stars in one go, we can now make a census of all the stars in this part of the Milky Way,” Minniti said.

The color-magnitude diagram of the bulge contains information about the structure and content of the Milky Way. ESO said one interesting result revealed from the data is the large number of faint red dwarf stars.

“One of the other great things about the VVV survey is that it´s one of the ESO VISTA public surveys. This means that we´re making all the data publicly available through the ESO data archive, so we expect many other exciting results to come out of this great resource," Saito concluded.