These three images taken by NASA's Hubble Space Telescope reveal the emergence of an exploding star, called a supernova.
Nicknamed SN Primo, the exploding star belongs to a special class called Type Ia supernovae, which are distance markers used for studying dark energy and the expansion rate of the universe. Type Ia supernovae most likely arise when white dwarf stars – the burned-out cores of normal stars – siphon too much material from their companion stars and explode.
The top image shows part of the Hubble Ultra Deep Field, the region where astronomers were looking for a supernova blast. The white box pinpoints the area where the supernova is later seen. The image combines observations taken in visible and near-infrared light with the Advanced Camera for Surveys and the Wide Field Camera 3.
The image at bottom left, taken by the Wide Field Camera 3, is a close-up of the field without the supernova.
A new bright object, identified as the supernova, appears in the Wide Field Camera 3 image at bottom right.
The exploding star was discovered as part of a search for distant Type Ia supernovae called the CANDELS+CLASH Supernova Project.
The supernova team's search technique involved taking multiple near-infrared images over several months, looking for a supernova's faint glow. Once the team spotted the stellar blast in October 2010, they used WFC3's spectrometer to verify SN Primo's distance and to decode its light, finding the unique signature of a Type Ia supernova. The team then re- imaged SN Primo periodically for several months, measuring the slow dimming of its light.