Article Posted on : - Feb 07, 2011

LONDON (PTI): Planetary scientists claim to have discovered a new stream of stars in the Milky Way, the galaxy in which the Solar System is located.

The international study, led by Dr Mary Williams of the Astrophysical Institute Potsdam, is part of the Radial Velocity Experiment (RAVE) and used data from Siding Spring Observatory to measure the velocities of 250,000 stars.

The new "Aquarius Stream" is named after the constellation of Aquarius in which it resides.

The stream of stars is a remnant of a smaller galaxy in our cosmic neighbourhood, which was pulled apart by the gravitational pull of the Milky Way about 700 million years ago.

Dr Williams said the Aquarius Stream was particularly hard to find, located deep within the Milky Way where it was indistinguishable from the huge quantity of stars blocking our view of it.

"It was right on our doorstep, but we just couldn't see it," she said.

The astronomers used the RAVE data to draw conclusions about the formation of the Milky Way. She said that by astronomical standards, the 700-million-year-old Aquarius stream is exceptionally young.

Other known streams of stars located on the outskirts of our galaxy are billions of years old.

Professor Matthias Steinmetz, project leader of the multinational RAVE collaboration said he is optimistic the method used by Dr Williams and her team will lead to many more discoveries of this kind.

"We want to understand the formation history of our Milky Way. We want to find out how frequently constellations have merged with neighbouring galaxies in the past, and how many we are to expect in the future," he said.

While much about the galaxy surrounding planet Earth remains unknown, astronomers are certain about one thing -- the Milky Way's next huge collision will be with the Andromeda galaxy. This cosmic collision is predicted to take place in about three billion years -- unless one of the dwarf galaxies discovered over the past few years beats Andromeda to it.

RAVE is a multinational project, involving planetary scientists from Australia, Germany, France, Italy, Canada, the Netherlands, Switzerland, Slovenia, the UK and USA.