S-brane

S-branes are hypothetical counterparts of D-branes. The S-brane, is localized in time, unlike the D-brane. The "S" could stand for:

• Ashoke Sen

• Andrew Strominger

• Spacelike

The S-brane was originally proposed by Andrew Strominger in a speculative paper. 

Another version of S-branes were studied by Ashoke Sen.

They are thought to be extended in spacelike and temporal directions. They exist only at one point in time. Otherwise, they are analogous to p-branes.