The FINANCIAL -- NASA's
Hubble Space Telescope has looked deep into the distant universe and
detected the feeble glow of a star that exploded more than 9 billion
years ago, according to NASA.
The sighting is the first finding of an ambitious survey that will help astronomers place better constraints on the nature of dark energy, the mysterious repulsive force that is causing the universe to fly apart ever faster.The stellar explosion, nicknamed SN Primo, belongs to a special class called Type Ia supernovae, which are bright beacons used as distance markers for studying the expansion rate of the universe. Type Ia supernovae likely arise when white dwarf stars, the burned-out cores of normal stars, siphon too much material from their companion stars and explode.
SN Primo is the farthest Type Ia supernova with its distance confirmed through spectroscopic observations. In these types of observations, a spectrum splits the light from a supernova into its constituent colors. By analyzing those colors, astronomers can confirm its distance by measuring how much the supernova's light has been stretched, or red-shifted, into near-infrared wavelengths because of the expansion of the universe.
The supernova was discovered as part of a three-year Hubble program to survey faraway Type Ia supernovae, opening a new distance realm for searching for this special class of stellar explosion. The remote supernovae will help astronomers determine whether the exploding stars remain dependable cosmic yardsticks across vast distances of space in an epoch when the cosmos was only one-third its current age of 13.7 billion years.
Called the CANDELS+CLASH Supernova Project, the census uses the sharpness and versatility of Hubble's Wide Field Camera 3 to assist astronomers in the search for supernovae in near-infrared light and verify their distance with spectroscopy. CANDELS is the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey and CLASH is the Cluster Lensing and Supernova Survey.
The new results were presented on Jan. 11 at the American Astronomical Society meeting in Austin, Texas.
The supernova team's search technique involved taking multiple near-infrared images over several months, looking for a supernova's faint glow. After 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 eight months, measuring the slow dimming of its light.
By taking the census, the astronomers hope to determine the frequency of Type Ia supernovae during the early universe and glean insights into the mechanisms that detonated them.If astronomers discover that Type Ia supernovae begin to depart from how they expect them to look, they might be able to gauge those changes and make the measurements of dark energy more precise. Riess and two other astronomers shared the 2011 Nobel Prize in Physics for discovering dark energy 13 years ago, using Type Ia supernova to plot the universe's expansion rate.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
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