NuSTAR telescope takes observes core of supernova

Cassiopeia A is among the best-studied supernova remnants. 

This image blends data from NASA's Spitzer (red), Hubble (yellow), and Chandra (green and blue) observatories. 

Credit: NASA /JPL-Caltech /STScI /CXC /SAO

Astronomers have peered for the first time into the heart of an exploding star in the final minutes of its existence.

The feat by the high-energy X-ray satellite NuSTAR provides details of the physics of the core explosion inaccessible until now, says team member Steven Boggs of UC Berkeley.

NuSTAR mapped radioactive titanium in the Cassiopeia A supernova remnant, which has expanded outward and become visible from Earth since the central star exploded in 1671.

Astronomers for the first time have peered into the heart of an exploding star in the final minutes of its existence.

The feat is one of the primary goals of NASA's NuSTAR mission, launched in June 2012 to measure high-energy X-ray emissions from exploding stars, or supernovae, and black holes, including the massive black hole at the center of our Milky Way Galaxy.

The NuSTAR team reported in this week's issue of the journal Nature the first map of titanium thrown out from the core of a star that exploded in 1671.

That explosion produced the beautiful supernova remnant known as Cassiopeia A (Cas A).

The well-known supernova remnant has been photographed by many optical, infrared and X-ray telescopes in the past, but these revealed only how the star's debris collided in a shock wave with the surrounding gas and dust and heated it up.

NuSTAR has produced the first map of high-energy X-ray emissions from material created in the actual core of the exploding star: the radioactive isotope titanium-44, which was produced in the star's core as it collapsed to a neutron star or black hole.

The energy released in the core collapse supernova blew off the star's outer layers, and the debris from this explosion has been expanding outward ever since at 5,000 kilometers per second.

Steven Boggs

"This has been a holy grail observation for high energy astrophysics for decades," said coauthor and NuSTAR investigator Steven Boggs, UC Berkeley professor and chair of physics.

"For the first time we are able to image the radioactive emission in a supernova remnant, which lets us probe the fundamental physics of the nuclear explosion at the heart of the supernova like we have never been able to do before."

"Supernovae produce and eject into the cosmos most of the elements are important to life as we know it," said UC Berkeley professor of astronomy Alex Filippenko, who was not part of the NuSTAR team.

Alex Filippenko

"These results are exciting because for the first time we are getting information about the innards of these explosions, where the elements are actually produced."

Boggs says that the information will help astronomers build three-dimensional computer models of exploding stars, and eventually understand some of the mysterious characteristics of supernovae, such as jets of material ejected by some.

Previous observations of Cas A by the Chandra X-ray telescope, for example, showed jets of silicon emerging from the star.

Fiona Harrison

"Stars are spherical balls of gas, and so you might think that when they end their lives and explode, that explosion would look like a uniform ball expanding out with great power," said Fiona Harrison, the principal investigator of NuSTAR at the California Institute of Technology.

"Our new results show how the explosion's heart, or engine, is distorted, possibly because the inner regions literally slosh around before detonating."

More information: Study paper: dx.doi.org/10.1038/nature12997

NASA Chandra Image: Cassiopeia A supernova

This colourful image of Cassiopeia A, taken by the Chandra X-Ray Observatory in 2009, shows an exploded star 11,000 light-years away. 

The green ring surrounding the supernova is from the initial shock wave generated by the explosion; it measures 10 light years in diameter. 

The bright blue areas are nearly pure iron gas from the hottest part of the star.

Credit: NASA Chandra

Exploring the Third Dimension of Cassiopeia A

One of the most famous objects in the sky - the Cassiopeia A supernova remnant - will be on display like never before, thanks to NASA's Chandra X-ray Observatory and a new project from the Smithsonian Institution.

A new three-dimensional (3D) viewer, being unveiled this week, will allow users to interact with many one-of-a-kind objects from the Smithsonian as part of a large-scale effort to digitize many of the Institutions objects and artifacts.

Scientists have combined data from Chandra, NASA's Spitzer Space Telescope, and ground-based facilities to construct a unique 3D model of the 300-year old remains of a stellar explosion that blew a massive star apart, sending the stellar debris rushing into space at millions of miles per hour.

The collaboration with this new Smithsonian 3D project will allow the astronomical data collected on Cassiopeia A, or Cas A for short, to be featured and highlighted in an open-access program -- a major innovation in digital technologies with public, education, and research-based impacts.

To coincide with Cas A being featured in this new 3D effort, a specially-processed version of Chandra's data of this supernova remnant is also being released.

This new image shows with better clarity the appearance of Cas A in different energy bands, which will aid astronomers in their efforts to reconstruct details of the supernova process such as the size of the star, its chemical makeup, and the explosion mechanism.

The colour scheme used in this image is the following: low-energy X-rays are red, medium-energy ones are green, and the highest-energy X-rays detected by Chandra are coloured blue.

Cas A is the only astronomical object to be featured in the new Smithsonian 3D project. This and other objects in the collection - including the Wright brothers plane, a 1,600-year-old stone Buddha, a gunboat from the Revolutionary War, and fossil whales from Chile -- were being showcased in the Smithsonian X 3D event, taking place on November 13th and 14th at the Smithsonian in Washington, DC.

In addition to new state-of-the-art 3D viewer, the public will be able to explore these objects through original videos, online tours, and other supporting materials.

Cas A is the only supernova remnant to date to be modeled in 3D. To create this visualization, unique software that links the fields of astrophysics and medical imaging (known as "astronomical medicine") was used.

Since its initial release in 2009, the 3D model has proven a rich resource for scientists as well as an effective tool for communicating science to the public.

Providing this newly formatted data in an open source framework with finely-tuned contextual materials will greatly broaden awareness and participation for general public, teacher, student and researcher audiences.

Image credit: NASA/CXC/SAO

NuSTAR X-Ray Telescope image: Supernova Remnant Cassiopeia A

The supernova Cassiopeia A, as seen by the NuSTAR X-ray telescope

Image: DSS/JPL-Caltech/NASA

A space telescope has peered through dense dust and gas to produce the first images of the high-energy cosmos. These reveal two blazing black holes and a supernova remnant (see pictures, right).

The Nuclear Spectroscopic Telescope Array, or NuSTAR, was launched into Earth orbit on 13 June. It can detect X-ray radiation at energies between 6 and 79 kilo electronvolts, well above the range of NASA's other orbiting telescopes, such as Chandra.

Such high-energy radiation can penetrate gas and dust, so NuSTAR sees through the galactic debris that blinds other telescopes.

On 7 January, Fiona Harrison of the California Institute of Technology in Pasadena, released the telescope's first images at a meeting of the American Astronomical Society (AAS) in Long Beach, California.

One image (see picture, right) is of the supernova remnant Cassiopeia A, which is about 11,000 light years from us. It shows never-seen-before high-energy X-rays emitted from extremely hot regions and from particles accelerated to within a fraction of the speed of light by the supernova's shock wave.