An international team of astronomers using the Hubble Space Telescope has found the most distant Type Ia supernova ever detected.

The supernova, labeled SN UDS10Wil and nicknamed SN Wilson after the 28th U.S. president Woodrow Wilson, exploded more than 10 billion years ago, smashing the previous record by roughly 350 million years.

SN UDS10Wil belongs to a class of exploding stars known as Type Ia supernovae. These objects are prized by astronomers because they can be used as a yardstick for measuring cosmic distances, thereby yielding clues to the nature of dark energy, the mysterious force accelerating the rate of expansion of the Universe.

“This new distance record holder opens a window into the early Universe, offering important new insights into how these supernovae form,” said Dr David Jones of the Johns Hopkins University in Baltimore, lead author of a paper reporting the discovery in the Astrophysical Journal (arXiv.org version).

“At that epoch, we can test theories about how reliable these detonations are for understanding the evolution of the Universe and its expansion.”

One of the debates surrounding Type Ia supernovae is the nature of the fuse that ignites them. This latest discovery adds credence to one of two competing theories of how they explode. Although preliminary, the evidence favors the explosive merger of two burned out stars – small, dim, and dense stars known as white dwarfs, the final state for stars like our Sun.

The discovery was part of a three-year Hubble program called the CANDELS+CLASH Supernova Project. This program aimed to survey faraway Type Ia supernovae to determine their distances and see if their behavior has changed over the 13.8 billion years since the Big Bang.

So far, CANDELS+CLASH has uncovered more than 100 supernovae of all types that exploded from 2.4 to over 10 billion years ago. The team has identified eight of these discoveries as Type Ia supernovae that exploded more than 9 billion years ago — including this new record-breaker, which, although only four percent older than the previous record holder, pushes the record roughly 350 million years further back in time.

Finding remote supernovae opens up the possibility to measure the Universe’s accelerating expansion due to dark energy. However, this is an area that is not fully understood — and nor are the origins of Type Ia supernovae.

“This new result is a really exciting step forward in our study of supernovae and the distant Universe,” said co-author Dr Jens Hjorth of the Dark Cosmology Center at the Niels Bohr Institute, University of Copenhagen. “We can begin to explore and understand the stars that cause these violent explosions.”

______

Bibliographic information: David O. Jones et al. 2013. The Discovery of the Most Distant Known Type Ia Supernova at Redshift 1.914. Accepted for publication in ApJ; arXiv: 1304.0768