Berlin, May 31 (IANS/EFE): An international team of astronomers is challenging the prevalent theory on how the lives of most stars end, the European Southern Observatory, or ESO, said.

"Astronomers expect that stars like the Sun will blow off much of their atmospheres into space near the ends of their lives. But new observations of a huge star cluster made using ESO's Very Large Telescope have shown - against all expectations - that a majority of the stars studied simply did not get to this stage in their lives at all," the observatory said in a statement.

The majority of stars gradually cool over a period of millions of years, the astronomers found.

"The way in which stars evolve and end their lives was for many years considered to be well understood. Detailed computer models predicted that stars of a similar mass to the Sun would have a period toward the ends of their lives - called the asymptotic giant branch, or AGB - when they undergo a final burst of nuclear burning and puff off a lot of their mass in the form of gas and dust," the ESO said.

The astronomers found that the amount of sodium in stars was a strong predictor of how they ended their lives, the ESO said.

"For a stellar modelling scientist this suggestion was crazy! All stars go through the AGB phase according to our models. I double-checked all the old studies but found that this had not been properly investigated. I decided to investigate myself, despite having little observational experience," Monash University Center for Astrophysics stellar theory expert Simon Campbell said.

The astronomers' conclusions are based on observations made using the ESO's La Silla Observatory in Chile.

Astronomers studied "the light coming from stars in the globular star cluster NGC 6752 in the southern constellation of Pavo (The Peacock)", the ESO said.