Between our Galaxy and its dwarf companions, the Large and Small Magellanic Clouds, stretches the long Magellanic Stream, a stream of gas and dust. This stream, which is estimated to be two to three hundred million suns, stretches 600,000 thousand light-years across. Although astronomers have long hypothesized that there must be stars in the Magellanic Stream, it was impossible to observe them until recently.
However, using data from the Gaia telescope, scientists have managed to spot the first stars in the Magellanic Stream. In a paper by American and Australian scientists, published in the library of preprints of Cornell University, reports on this discovery.
The Magellanic Stream is thought to be formed by matter flowing from dwarf galaxies to our Galaxy. Studying stars in this flow can help scientists better understand the intensity of this movement, as well as the history and future of the Magellanic Clouds.
For their study, astronomers used the Gaia data catalog, which includes information on the positions and velocities of more than a billion stars. By selecting stars moving with the Milky Way and choosing stars with chemical compositions consistent with the Magellanic Stream, the scientists were able to identify 13 stars likely to belong to the stream. These stars, red giants, are between 200,000 and 325,000 light-years away from us.
Interestingly, however, some of these stars have low metallicity, which may indicate that they are very old. This composition is not very typical of the Magellanic Stream, so the history of this stream may be more complicated than previously thought.
This discovery allows scientists to further explore the connections between our Galaxy and its dwarf satellites. They will be able to better understand the intensity of matter flow between galaxies, as well as predict the future of the Magellanic Clouds.