AN INTERNATIONAL TEAM of astronomers has discovered a new stream of stars in our Milky Way, thanks to data collected at the ANU Siding Spring Observatory.
The research, led by Dr Mary Williams from the Astrophysical Institute Potsdam (AIP), is part of the Radial Velocity Experiment (RAVE) and used data from Siding Spring 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 Mary Williams, a former graduate student of the Research School of Astronomy and Astrophysics at ANU, 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,” said Dr Williams.
Dr Williams 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 at AIP 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,” he said. “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.”
While much about the galaxy surrounding our 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.
This video shows a highly speeded up computer simulation of the collision between the Milky Way and Andromeda. See what happens to the shape of the Milky Way following the collision:
RAVE is a multinational project, involving scientists from Australia, Germany, France, UK, Italy, Canada, the Netherlands, Switzerland, Slovenia and the USA.
Adapted from information issued by ANU. Images courtesy ANU and Hubble Heritage Team (AURA / STScI / NASA / ESA).
Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz