Milky Way’s fast-moving galactic hypervelocity stars may have come from another galaxy

From ABC Science, 5 July 2017

The fastest-moving stars in our galaxy may have been shot off the bow of a passing smaller galaxy.

These so-called “galactic hypervelocity stars” are large and short-lived but travel up to 1,000 kilometres per second.

Strangely, most of them appear to be in an unusual cluster in the northern hemisphere sky, and the origin of these huge speedsters has been a bit of a puzzle.

But now, researchers from the University of Cambridge argue these stars may have been flung off the front of the Large Magellanic Cloud, a dwarf galaxy travelling at high speed past the edge of the Milky Way galaxy.

The findings of their new modelling study are published in the current Monthly Notices of the Royal Astronomical Society. Read more.