Narrator (Joseph DePasquale, CXC): Astronomers estimate that a star explodes as a supernova in our Galaxy, on average, about twice per century. In 2008, a team of scientists announced they discovered the remains of a supernova that is the most recent, in Earth’s time frame, known to have occurred in the Milky Way. The explosion would have been visible from Earth a little more than a hundred years ago, if it hadn't been heavily obscured by dust and gas. Today, that object is known as the supernova G1.9+0.3 or G1.9 for short. A new long observation -- equivalent to more than 11 days of Chandra time -- of explosion's debris field is providing new details about G1.9. The source of G1.9 was most likely a white dwarf star that underwent a thermonuclear detonation and was destroyed – either after merging with another white dwarf or by pulling too much material from an orbiting companion star. The explosion ejected the remains of the destroyed star, creating the supernova remnant seen today by Chandra and other telescopes. The new Chandra data show that the explosion that created G1.9 was different than other supernovas like it. For starters, the remnant's debris is unevenly distributed, while most other supernova remnant are highly symmetrical. Also, researchers found that some of the debris – particularly iron that would have been in the star's core before the explosion -- is moving at extremely high speeds. By combining these clues from the Chandra data with theoretical models, scientists think that the explosion that created G1.9 must have been highly irregular and abnormally energetic.
Revised: May 19, 2022