New measurements adopted by an international team of researchers have revealed a much "slimmer" Milky Way compared with previous estimates.
According to a press release from Germany's Max Planck Institute for Astronomy (MPIA) on Tuesday, the research led by Xiangxiang Xue of the National Astronomy Observatories of China has put the mass of the Milky Way at slightly under one trillion times the mass of the sun.
By contrast, the most recent previous studies of the mass of the Milky Way yielded values of up to two trillion times the mass of the sun for the total mass of the galaxy.
Xue, who is currently pursuing a doctoral thesis at the Heidelberg-based MPIA, told Xinhua in a telephone interview that the new results do not mean that the Milky Way has actually become slimmer. It is rather the result of more accurate measurements.
The discovery was based on data from the Sloan Digital Sky Survey (SDSS-II) of Apache Point Observatory in New Mexico, the United States.
To trace the mass distribution of the Galaxy, Xue's team used acarefully constructed sample of 2,400 "blue horizontal branch" stars. In comparison, previous studies used mixed samples of only 50 to 500 stars.
"The much larger sample of stars and computer simulations of the Galaxy allow us to produce more accurate measurements," Xue said.
The new research has been accepted for publication in The Astrophysical Journal.
Hans-Walter Rix, director of MPIA, told Xinhua that one of the implications of the research could be that there is much less of the mysterious 'dark matter' at long distances from the Milky Way's center than previously thought.
He also said that if the Milky Way has less mass, its ability to force its satellite galaxies to orbit around it would be reduced considerably.
"Indeed, the new results imply that the 'Magellanic Clouds,' the Milky Way's most famous satellite galaxies, may not orbit our own galaxy regularly, as previously thought, but are maybe only fleeting visitors in our neighborhood, flying off again to great distances," Rix said.
Moreover, he noted that if the overall mass of the Milky Way was only half as much as previously thought, there would be only half as much gas from which to form stars.
"Because the amount of stars in the Milky Way has not changed, but the material from which they can have formed has halved...the Milky Way must have been exceptionally effective in forming stars," he said.
"Since we live on a planet, naturally orbiting a star, the chance of finding ourselves in a galaxy like the Milky Way of course increases with the Milky Way's ability to form stars with planets. It is intriguing to think about whether our own existence on a planet around a star is related with the Milky Way's great efficiency to make stars like our Sun," Rix added.
Source:Xinhua
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