Sigma Orionis star cluster

The Sigma Orionis star cluster is a young open cluster, 1 to 5 million years old, that is part of the Orion OB Association, adjacent to the Horsehead Nebula; the star Sigma Orionis lies at its center. Within this cluster have been identified a number of free floating brown dwarf and large planet candidates.


Sigma Orionis star cluster
Three of the objects (reddish, marked by triangles) in the sigma Orionis star cluster that may be free-floating planets. Credit: Zapatero Osorio, et al./Science