The Sco–Cen OB association is the main part of a large complex of recent (<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 gravitationally unbound. 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 in the vicinity of the solar system about two million years ago. Iron-60 is also found in sediments from 8 million years ago.
References[change | change source]
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- Preibisch, T. & Mamajek E. 2009. "The nearest OB Association: Scorpius-Centaurus (Sco OB2)". Handbook of Star-Forming Regions 2: 0.
- Madsen S. et al 2002. "Astrometric radial velocities. III. Hipparcos measurements of nearby star clusters and associations". Astronomy & Astrophysics 381 (2): 446–463. doi:10.1051/0004-6361:20011458.
- = no longer held together by gravity
- de Geus E.J. (1992). "Interaction of stars and interstellar matter in Scorpio Centaurus". Astronomy & Astrophysics 262: 258–270.
- Belinda Smith (Aug 9, 2016). "Ancient bacteria store signs of supernova smattering". Cosmos. https://cosmosmagazine.com/space/ancient-bacteria-store-signs-of-supernova-smattering.
- Peter Ludwig et al. (Aug 16, 2016). "Time-resolved 2-million-year-old supernova activity discovered in Earth’s microfossil record". PNAS. doi:10.1073/pnas.1601040113.
- Colin Barras (Oct 14, 2017). "Fires may have given our evolution a kick-start". New Scientist. https://www.newscientist.com/article/mg23631474-400-exploding-stars-could-have-kickstarted-our-ancestors-evolution/.