University of California, Santa Barbara | 2015 May 20
Team of astronomers including scientists from UCSB observe supernova smash into
companion star; resulting ultraviolet pulse points to supernova’s origin story
The origin of type Ia supernovae, the standard candles used to reveal the presence of dark energy in the universe, is one of astronomy’s most beguiling mysteries. Astronomers know they occur when a white dwarf explodes in a binary system with another star, but the properties of that second star — and how it triggers the explosion — have remained elusive for decades.[attachment=0]sn-star.jpg[/attachment]
Now, a team of astronomers from the intermediate Palomar Transient Factory (iPTF), including those associated with UC Santa Barbara, have witnessed a supernova smashing into a nearby star, shocking it, and creating an ultraviolet glow that reveals the size of the companion. The discovery involved the rapid response and coordination of iPTF, NASA’s Swift satellite and the new capabilities of the Las Cumbres Observatory Global Telescope Network (LCOGT).
The supernova, named iPTF14atg, is located 300 million lightyears away in the galaxy IC831. The study, appearing in the May 21 issue of Nature, was led by graduate student Yi Cao of Caltech, but included physics postdoctoral fellows Iair Arcavi and Stefano Valenti, and physics faculty member Andrew Howell of UCSB and LCOGT.
In a type Ia supernova, a white dwarf star explodes after it gains matter from a companion star in the same binary star system. One of the leading theories is that the supernova happens when two white dwarf stars merge. But a competing theory says that the companion could be a normal or giant star that survives the explosion, although not without some damage. The supernova is expected to hit the companion star, creating a shock wave that glows in ultraviolet light. This had been theorized in 2010, but such an effect had never been seen. This and other factors led many to conclude that most type Ia supernovae arise from the mergers of two white dwarf stars. ...
Astronomers Observe a Supernova Colliding with Its Companion Star
California Institute of Technology | 2015 May 20
Supernova Hunting with Supercomputers
Lawrence Berkeley National Laboratories | 2015 May 20
Strong UV Pulse Reveals Supernova's Origin Story
Carnegie Institution for Science | 2015 May 20
A strong ultraviolet pulse from a newborn type Ia supernova - Yi Cao et al
- Nature 521(7552) 328 (21 May 2015) DOI: 10.1038/nature14440
