Light echo around LRLL 54361

This sequence of images from the NASA/ESA Hubble Space Telescope shows a pulse of light emanating from the protostellar object LRLL 54361. Most if not all of this light results from scattering off circumstellar dust in the protostellar envelope.

An apparent edge-on disk visible at the centre of the object, and three separate structures are interpreted as outflow cavities. The extent and shape of the scattered light changes substantially over a 25.3-day period.

This is caused by the propagation of the light pulse through the nebula. Astronomers propose that the flashes are due to material in a circumstellar disk suddenly being dumped onto a binary pair of forming stars. This unleashes a blast of radiation each time the stars get close to each other in their orbit.

These near-infrared light images are from Hubble’s Wide Field Camera 3.