Hubble Breaks Record in Search for Farthest Supernova

April 04, 2013

J.D. Harrington
Headquarters, Washington
202-358-5241
j.d.harrington@nasa.gov

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4514
villard@stsci.edu


RELEASE: 13-086

HUBBLE BREAKS RECORD IN SEARCH FOR FARTHEST SUPERNOVA

WASHINGTON -- NASA's Hubble Space Telescope has found the farthest
supernova so far of the type used to measure cosmic distances.
Supernova UDS10Wil, nicknamed SN Wilson after American President
Woodrow Wilson, exploded more than 10 billion years ago.

SN Wilson belongs to a special class called Type Ia supernovae. These
bright beacons are prized by astronomers because they provide a
consistent level of brightness that can be used to measure the
expansion of space. They also yield clues to the nature of dark
energy, the mysterious force accelerating the rate of expansion.

"This new distance record holder opens a window into the early
universe, offering important new insights into how these stars
explode," said David O. Jones of Johns Hopkins University in
Baltimore, Md., an astronomer and lead author on the paper detailing
the discovery. "We can test theories about how reliable these
detonations are for understanding the evolution of the universe and
its expansion."

The discovery was part of a three-year Hubble program, begun in 2010,
to survey faraway Type Ia supernovae and determine whether they have
changed during the 13.8 billion years since the explosive birth of
the universe. Astronomers took advantage of the sharpness and
versatility of Hubble's Wide Field Camera 3 to search for supernovae
in near-infrared light and verify their distance with spectroscopy.
Leading the work is Adam Riess of the Space Telescope Science
Institute in Baltimore, Md., and Johns Hopkins University.

Finding remote supernovae provides a powerful method to measure the
universe's accelerating expansion. So far, Riess's team has uncovered
more than 100 supernovae of all types and distances, looking back in
time from 2.4 billion years to more than 10 billion years. Of those
new discoveries, the team has identified eight Type Ia supernovae,
including SN Wilson, that exploded more than 9 billion years ago.

"The Type Ia supernovae give us the most precise yardstick ever built,
but we're not quite sure if it always measures exactly a yard," said
team member Steve Rodney of Johns Hopkins University. "The more we
understand these supernovae, the more precise our cosmic yardstick
will become."

Although SN Wilson is only 4 percent more distant than the previous
record holder, it pushes roughly 350 million years farther back in
time. A separate team led by David Rubin of the U.S. Energy
Department's Lawrence Berkeley National Laboratory in California
announced the previous record just three months ago.

Astronomers still have much to learn about the nature of dark energy
and how Type Ia supernovae explode.
By finding Type Ia supernovae so early in the universe, astronomers
can distinguish between two competing explosion models. In one model
the explosion is caused by a merger between two white dwarfs. In
another model, a white dwarf gradually feeds off its partner, a
normal star, and explodes when it accretes too much mass.

The team's preliminary evidence shows a sharp decline in the rate of
Type Ia supernova blasts between roughly 7.5 billion years ago and
more than 10 billion years ago. The steep drop-off favors the merger
of two white dwarfs because it predicts that most stars in the early
universe are too young to become Type Ia supernovae.

"If supernovae were popcorn, the question is how long before they
start popping?" Riess said. "You may have different theories about
what is going on in the kernel. If you see when the first kernels
popped and how often they popped, it tells you something important
about the process of popping corn."

Knowing the type of trigger for Type Ia supernovae also will show how
quickly the universe enriched itself with heavier elements such as
iron. These exploding stars produce about half of the iron in the
universe, the raw material for building planets, and life.

The team's results have been accepted for publication in an upcoming
issue of The Astrophysical Journal.

The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency. NASA's Goddard Space
Flight Center in Greenbelt, Md., manages the telescope. The Space
Telescope Science Institute (STScI) in Baltimore, Md., conducts
Hubble science operations. The Association of Universities for
Research in Astronomy Inc., in Washington operates STScI.

For images and more information about SN Wilson, visit:

http://hubblesite.org/news/2013/11

For more information about NASA's Hubble Space Telescope, visit:


http://www.nasa.gov/hubble


-end-



To subscribe to the list, send a message to:
hqnews-subscribe@mediaservices.nasa.gov
To remove your address from the list, send a message to:
hqnews-unsubscribe@mediaservices.nasa.gov