Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Closest, brightest supernova in decades is also a little weird

27.02.2014

Faster brightening than expected may typify cosmic yardstick Type Ia supernovae

A bright supernova discovered only six weeks ago in a nearby galaxy is provoking new questions about the exploding stars that scientists use as their main yardstick for measuring the universe.


This image features a color composite of SN 2014J in the 'cigar galaxy' M82, 11.4 million light years away, made from KAIT images obtained through several different filters. The supernova is marked with an arrow. Other round objects are relatively nearby stars in our own Milky Way Galaxy.

Credit: W. Zheng and A. Filippenko, University of California Berkeley

Called SN 2014J, the glowing supernova was discovered by a professor and his students in the United Kingdom on Jan. 21, about a week after the stellar explosion first became visible as a pinprick of light in its galaxy, M82, 11.4 million light years away. Still visible today through small telescopes in the Big Dipper, it is the brightest supernova seen from Earth since SN1987A, 27 years ago, and may be the closest Type Ia supernova – the kind used to measure cosmic distances – in more than 77 years.

When University of California, Berkeley, astronomer Alex Filippenko's research team looked for the supernova in data collected by the Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory near San Jose, Calif., they discovered that the robotic telescope had actually taken a photo of it 37 hours after it appeared, unnoticed, on Jan. 14.

Combining this observation with another chance observation by a Japanese amateur astronomer, Filippenko's team was able to calculate that SN 2014J had unusual characteristics – it brightened faster than expected for a Type Ia supernova and, even more intriguing, it exhibited the same unexpected, rapid brightening as another supernova that KAIT discovered and imaged last year – SN 2013dy.

"Now, two of the three most recent and best-observed Type Ia supernovae are weird, giving us new clues to how stars explode," said Filippenko, referring to a third, though apparently 'normal,' Type Ia supernova, SN 2011fe, discovered three years ago. "This may be teaching us something general about Type Ia supernovae that theorists need to understand. Maybe what we think of as 'normal' behavior for these supernovae is actually unusual, and this weird behavior is the new normal."

A paper describing the SN 2014J observations – the first published on this newly discovered supernova – was posted online this week by The Astrophysical Journal Letters and will appear in the March 1 print issue.

Type Ia supernovae as standard candles

Astronomers noticed decades ago that Type Ia supernovae explode with about the same brightness, no matter where they are in the universe. This makes them good "standard candles" with which to judge distance. In the 1990s, two teams (both of them included Filippenko) used Type Ia supernovae to determine the distances to galaxies, compared distance with velocity and discovered that the universe is expanding faster and faster, rather than slowing down as expected. The teams' leaders, including UC Berkeley astrophysicist Saul Perlmutter, shared the 2011 Nobel Prize in Physics for this discovery.

While the latest discoveries do not contradict these results, refinements in understanding Type Ia explosions could help improve distance measurements and lead to more precise calculations of the expansion rate of the universe, thereby setting constraints on the nature of "dark energy," a still mysterious energy comprising 70 percent of the universe and thought to be responsible for its acceleration.

The new data also provide information about the physics occurring in the core of the explosion.

A Type Ia supernova is thought to be the explosion of a white dwarf – an old and very dense star that has shrunk from the size of the Sun to the size of Earth. When a white dwarf has a stellar companion, it can sometimes gain matter from it until the white dwarf becomes unstable, completely obliterating itself through a gigantic nuclear explosion.

New telescopes to catch more supernovae

Because of the importance of supernovae in measuring the universe, many new telescopes, such as the Palomar Transient Factor in San Diego County and the Pan-STARRS in Hawaii, continually rescan the sky to discover more of them. The KAIT telescope has a smaller field of view than newer ones do, so Filippenko's team has switched its focus to discovering supernovae earlier: it scans the same patches of sky every night or every other night. The sooner a new explosion is discovered, the sooner astronomers can capture information, such as spectra showing how the supernova brightens in different colors or wavelengths.

Last year, for example, KAIT and Filippenko's Lick Observatory Supernova Search (LOSS) team discovered and photographed SN 2013dy within two and a half hours of its appearance, earlier than for any other Type Ia. KAIT, which is operated by postdoctoral scholar WeiKang Zheng, is programmed to automatically take images of likely supernovae in five different wavelength bands, and in 2012 captured one supernova, SN 2012cg, three minutes after its discovery.

"Very, very early observations give us the most stringent constraints on what the star's behavior really is in the first stages of the explosion, rather than just relying on theoretical speculation or extrapolating back from observations at later times, which is like observing adolescents to understand early childhood," Filippenko said.

Filippenko's colleagues include Zheng; UC Berkeley graduate student Isaac Shivvers; assistant specialist Kelsey I. Clubb; postdoctoral scholars Ori D. Fox, Melissa L. Graham, Patrick L. Kelly and Jon C. Mauerhan; and amateur astronomer Koichi Itagaki of the Itagaki Astronomical Observatory in Yamagata, Japan, who captured an image of SN 2014J just 20 hours after it exploded.

The research was funded by the TABASGO Foundation, the Sylvia & Jim Katzman Foundation, the Christopher R. Redlich Fund, Gary and Cynthia Bengier, the Richard and Rhoda Goldman Fund, Weldon and Ruth Wood, and the National Science Foundation.

Robert Sanders | EurekAlert!

More articles from Physics and Astronomy:

nachricht Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters

nachricht Theorists publish highest-precision prediction of muon magnetic anomaly
16.07.2018 | DOE/Brookhaven National Laboratory

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides

16.07.2018 | Life Sciences

New research calculates capacity of North American forests to sequester carbon

16.07.2018 | Earth Sciences

Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication

16.07.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>