Nav: Home

Astrophysicists report radioactive cobalt in supernova explosion

August 29, 2014

A group of astrophysicists, including researchers from MIPT, have detected the formation of radioactive cobalt during a supernova explosion, lending credence to a corresponding theory of supernova explosions. Details are given in the journal Nature, one of the most cited scientific publications in the world.

The article's main author, Yevgeny Churazov (Space Research Institute of the Russian Academy of Sciences), together with his co-authors, including Sergei Sazonov of the Space Research Institute and MIPT, reported the results of their analysis of data collected with the INTEGRAL gamma-ray orbital telescope, which they used to detect the radioactive isotope cobalt-56(56Co).

Isotope 56Co has a half-life of just 77 days, and does not exist in normal conditions. However, during a giant thermonuclear explosion of a supernova, this short-lived radioactive isotope is produced in large quantities.

Radiating cobalt was registered at the supernova SN2014J, located 11 million light-years from Earth

Astrophysicists never obtained similar spectra before. The reason was the rarity of explosions at such a distance - 11 million light-years is a large value on the galactic scale (the diameter of a galaxy is about 100,000 light-years, the distance between stars is a few light-years), but on an intergalactic scale it is a relatively short distance. There are several hundreds of galaxies within a radius of ten million light-years; supernovae produce explosions like this (type Ia explosions) once every few centuries in a galaxy. For example, a type Ia supernova last exploded in the Milky Way in 1606.

SN2014J was registered on January 21, 2014 by astronomer Steve Fossey and a group of students from University College London in the galaxy M82. Fossey reported the discovery, and several observatories, including INTEGRAL, started observations immediately. Russian researchers spent a million seconds of their quota for the use of the INTEGRAL telescope to study the supernova. In addition to the spectra, they obtained data on how the brightness of radiation changes over time.

According to a theory that was developed earlier, during an explosion of the Ia type, the remnants of a star barely radiate in the gamma range the first dozens of days. The star's shell is opaque in this region of the spectrum; a supernova begins to produce gamma radiation only after the outer layer becomes sufficiently rarefied. By that time, radioactive nickel-56 with a half-life of 10 days, synthesized during the explosion, transforms into radioactive cobalt-56, the lines of which were detected by the researchers.

The essence of spectral analysis remains unchanged whatever the nature of radiation. For light, X-rays and even radio waves, scientists first plot a graph of a spectrum, or the relationship of intensity and frequency (or, equivalently, wavelength: wavelength is inversely proportional to frequency).

The graph's shape indicates the nature of the source of radiation and through what environment the radiation has passed. Spectral lines, or sharp peaks on such graphs, correspond to certain events like the emission or absorption of quanta by atoms during transition from one energy level to another.

During formation, cobalt-56 had a surplus of energy, exhausted in the form of gamma rays with energies of 847 keV and 1237keV; other isotopes produced radiation with quanta of different energies and thus could not be confused with cobalt-56.

The data collected by the INTEGRAL telescope also allowed the researchers to assess how much radioactive cobalt was emitted during the explosion - the equivalent of about 60% of the Sun's mass.

Over time, cobalt-56 turns into the most common isotope of iron, 56Fe.56Fe is the most common isotope because it can be obtained from nickel emitted during supernovae explosions (nickel turns into cobalt, and cobalt turns into iron).

Thus, the new results back up simulations of supernovae explosions and also confirm that our planet consists of matter that has gone through thermonuclear explosions of an astronomical scale.
-end-


Moscow Institute of Physics and Technology

Related Supernova Articles:

The big star that couldn't become a supernova
For the first time in history, astronomers have been able to watch as a dying star was reborn as a black hole.
Seeing quadruple: Four images of the same supernova, a rare find
Galaxies bend light through an effect called gravitational lensing that helps astronomers peer deeper into the cosmos.
Explosive material: The making of a supernova
Pre-supernova stars may show signs of instability for months before the big explosion
Search for stellar survivor of a supernova explosion
Astronomers have used the NASA/ESA Hubble Space Telescope to observe the remnant of a supernova explosion in the Large Magellanic Cloud.
Wispy remains of supernova explosion hide possible 'survivor'
This image, taken with NASA's Hubble Space Telescope, shows the supernova remnant SNR 0509-68.7, also known as N103B.
The dawn of a new era for Supernova 1987a
Three decades ago, astronomers spotted one of the brightest exploding stars in more than 400 years.
The supernova that wasn't: A tale of 3 cosmic eruptions
Long-term observations with the Hubble Space Telescope revealed that Eta Carinae, a very massive star system that has puzzled astronomers since it erupted in a supernova-like event in the mid 19th century, has a past that's much more violent than they thought.
Blue is an indicator of first star's supernova explosions
An international collaboration led by the Kavli Institute for the Physics and Mathematics of the Universe have discovered that the color of supernovae during a specific phase could be an indicator for detecting the most distant and oldest supernovae in the Universe -- more than 13 billion years old.
Nearby supernova ashes continue to rain on Earth
Traces of 60Fe detected in space indicate that a nearby supernova occurred within the last few million years.
Supernova iron found on the moon
Approximately two million years ago a star exploded in a supernova close to our solar system: Its traces can still be found today in the form of an iron isotope found on the ocean floor.

Related Supernova Reading:

Supernova (Amulet #8)
by Kazu Kibuishi (Author)

The Supernova Advisor: Crossing the Invisible Bridge to Exceptional Client Service and Consistent Growth
by Rob Knapp (Author)

Supernova (The Lightless Trilogy)
by C.A. Higgins (Author)

Supernova Explosions (Astronomy and Astrophysics Library)
by David Branch (Author), J. Craig Wheeler (Author)

Supernova
by Diane Anthony (Author)

Supernova Advisor Teams: A Pathway to Excellence
by Curtis C. Brown Jr. (Author), Robert D. Knapp (Author)

Supernova: The Knight, the Princess and the Falling Star
by Dewi Lestari (Author), Harry Aveling (Translator)

Supernova (Supernatural Superstar Book 1)

Champagne Supernovas: Kate Moss, Marc Jacobs, Alexander McQueen, and the '90s Renegades Who Remade Fashion
by Maureen Callahan (Author)

Supernova
by L. B. Gold (Author)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

The Right To Speak
Should all speech, even the most offensive, be allowed on college campuses? And is hearing from those we deeply disagree with ... worth it? This hour, TED speakers explore the debate over free speech. Guests include recent college graduate Zachary Wood, political scientist Jeffrey Howard, novelist Elif Shafak, and journalist and author James Kirchick.
Now Playing: Science for the People

#486 Volcanoes
This week we're talking volcanoes. Because there are few things that fascinate us more than the amazing, unstoppable power of an erupting volcano. First, Jessica Johnson takes us through the latest activity from the Kilauea volcano in Hawaii to help us understand what's happening with this headline-grabbing volcano. And Janine Krippner joins us to highlight some of the lesser-known volcanoes that can be found in the USA, the different kinds of eruptions we might one day see at them, and how damaging they have the potential to be. Related links: Kilauea status report at USGS A beginner's guide to Hawaii's otherworldly...