Supernovas & Supernova Remnants

We are delighted to welcome Laura Lopez as a guest blogger today. Laura is first author of a paper describing the rare explosion that may have created the youngest known black hole in our Galaxy. Laura Lopez is currently a NASA Einstein Fellow and Pappalardo Fellow in Physics at MIT. Laura received her PhD in astronomy & astrophysics from the University of California Santa Cruz in 2011. Before her time at UCSC, she earned her bachelors degree in physics from MIT in 2004. Laura is originally from Barrington, IL, a northwest suburb of Chicago. Her research focuses on probing the beginning and ending of the stellar life cycle: how stars are born and how stars end their lives through supernova explosions.

A few years ago when I was a bright-eyed PhD student, I stumbled upon a press release making a provocative argument: a thousand year old supernova remnant in our Galaxy called W49B may have formed from a gamma-ray burst. Gamma-ray bursts (GRBs) are extreme supernova explosions thought to mark the end of the lives of some very massive stars, and they are the most energetic and luminous events in the Universe. Although astronomers have now found several hundred gamma-ray bursts, these explosions tend to be billions of light years away. So the claim that one may have occurred in our own Galaxy seemed astounding. It got me thinking: what would a gamma-ray burst look like after a thousand years, and what would it leave behind?

In 1604, a new star appeared in the night sky that was much brighter than Jupiter and dimmed over several weeks. This event was witnessed by sky watchers including the famous astronomer Johannes Kepler. Centuries later, the debris from this exploded star is known as the Kepler supernova remnant.

Astronomers have long studied the Kepler supernova remnant and tried to determine exactly what happened when the star exploded to create it. New analysis of a long observation from NASA's Chandra X-ray Observatory is providing more clues. This analysis suggests that the supernova explosion was not only more powerful, but might have also occurred at a greater distance, than previously thought.

Observations with NASA's Chandra X-ray Observatory have provided the first X-ray evidence of a supernova shock wave breaking through a cocoon of gas surrounding the star that exploded. This discovery may help astronomers understand why some supernovas are much more powerful than others.

A new X-ray study of the remains of an exploded star indicates that the supernova that disrupted the massive star may have turned it inside out in the process. Using very long observations of Cassiopeia A (or Cas A), a team of scientists has mapped the distribution of elements in the supernova remnant in unprecedented detail. This information shows where the different layers of the pre-supernova star are located three hundred years after the explosion, and provides insight into the nature of the supernova.

Vital clues about the devastating ends to the lives of massive stars can be found by studying the aftermath of their explosions. In its more than twelve years of science operations, NASA's Chandra X-ray Observatory has studied many of these supernova remnants sprinkled across the Galaxy.

Sometimes it's hard to get the connection between what happens far away in space and things that you can touch and feel on the ground. Of course, the science of "out there" is intertwined with the science of "right here." A new module for teachers in our Chandra Education section demonstrates that perfectly.

Dr. Gisela Dreschhoff

Since the 1970s, Dr. Gisela Dreschhoff has traveled to Antarctica and Greenland to study the effects from space imprinted on deep ice cores extracted from the ground. While she was initially interested in historic energetic events from the Sun, she has also looked at her data to see if some of the most famous supernova explosions – including Kepler, Tycho, and Cassiopeia A – have also left their mark in the ice.

With the holiday season in full swing, a new image from an assembly of telescopes has revealed an unusual cosmic ornament. Data from NASA's Chandra X-ray Observatory and ESA's XMM-Newton have been combined to discover a young pulsar in the remains of a supernova located in the Small Magellanic Cloud, or SMC. This would be the first definite time a pulsar, a spinning, ultra-dense star, has been found in a supernova remnant in the SMC, a small satellite galaxy to the Milky Way.

This image combines data from four different space telescopes to create a multi-wavelength view of all that remains of the oldest documented example of a supernova, called RCW 86. The Chinese witnessed the event in 185 A.D., documenting a mysterious "guest star" that remained in the sky for eight months. X-ray images from NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory are combined to form the blue and green colors in the image. The X-rays show the interstellar gas that has been heated to millions of degrees by the passage of the shock wave from the supernova.

G299.2-2.9 is an intriguing supernova remnant found about 16,000 light years away in the Milky Way galaxy . Evidence points to G299.2-2.9 being the remains of a Type Ia supernova, where a white dwarf has grown sufficiently massive to cause a thermonuclear explosion. Because it is older than most supernova remnants caused by these explosions, at an age of about 4500 years, G299.2-2.9 provides astronomers with an excellent opportunity to study how these objects evolve over time. It also provides a probe of the Type Ia supernova explosion that produced this structure.

A new movie from NASA's Chandra X-ray Observatory shows a sequence of Chandra images of the Crab Nebula, taken over an interval of seven months. Dramatic variations are seen, including the expansion of a ring of X-ray emission around the pulsar (white dot near center) and changes in the knots within this ring.