Astronomers have discovered a mysterious stream of ancient stars at the distant edges of the galaxy: a strange stellar breed so unlike any we’ve seen before, they may very well be the last of their kind.

This unusual collection of stars – called the ‘Phoenix stream’, after the Phoenix constellation in which they are visible – is what’s known as a stellar stream: an elongated chain of stars that used to exist in a spherical form, known as a globular cluster.

Such clusters can be torn asunder by a galaxy’s gravitational forces, in which case their globular form becomes warped, stretching out into a ghostly caravan of stars, fated to distantly orbit a faraway galactic core.