Scorpius–Centaurus Association

The Scorpius–Centaurus Association (sometimes called Sco–Cen or Sco OB2) is a group of stars near the Sun. They are 380 to 470 light years away.
They are young stars which all formed from the same cloud of material. They range from 11 to 15 million years old. They include the massive Antares, and most of the stars in the Southern Cross.
The Sco–Cen OB association is the main part of a large complex of recent (&lt;20 million years) and ongoing star-formation. The complex contains several star-forming molecular clouds in Sco–Cen's immediate vicinity.
The stellar members of the Sco–Cen association have nearly parallel velocity vectors, moving at about 20 km/s with respect to the Sun. The variation of velocity within the subgroups is about 1–2 km/s, and the group is most likely no longer held together by gravity. Several supernovae have exploded in Sco–Cen over the past 15 million years, leaving a network of expanding gas superbubbles around the group.
Iron-60 found in fossilised bacteria in sea floor sediments suggests there was a supernova near the solar system about 2,000,000 years ago. Iron-60 is also found in sediments from 8 million years ago.