Supernova Remnants: Dazzling Entrails of Violent Stellar Death

Even in death, there can be great beauty. Consider supernova remnants, the results of massive stars dying in great explosions, creating some of the most spectacular cosmic objects around.

Every 50 years or so, a star in our galaxy with more than 10 times the mass of our sun will expire. When such stars die, they go supernova, one of the most violent events in our universe. These explosions shoot off tons of material from the central star at up to 10 percent the speed of light.

Though the area surrounding stars seems empty, it is usually home to vast amounts of interstellar gas and dust. The supernova’s outburst runs into this surrounding material, creating a shockwave and heating it to temperatures greater than 10,000 Celsius. Over thousands of years, the local structure of the gas and dust shapes the stellar outpouring into shells, filaments, and other diffuse forms. Astronomers call these objects supernova remnants.

Supernova explosions and the remnants they leave behind have wide-ranging effects. They heat up the interstellar medium, creating complex chemistry out in space, and are responsible for accelerating protons and other atomic nuclei, which go zipping around the universe as cosmic rays. Perhaps most importantly, supernova explosions generate and liberate heavy elements, such as oxygen, carbon, and all metals, distributing them out into the wider cosmos. These elements eventually find their way into planetary systems, making life possible on at least one world that we know of.

Here, we take a look at some of the most famous and beautiful supernova remnants, giving you a chance to contemplate life, death, and cycles of renewal in the universe.


SN 1987A was a supernova in the outskirts of the Tarantula Nebula in the Large Magellanic Cloud, a nearby dwarf galaxy. As it was the first supernova discovered in 1987, it was labeled “1987A”. Its brightness peaked in May with an apparent magnitude of about 3 and slowly declined in the following months. It was the first opportunity for modern astronomers to see a supernova up close and observations have provided much insight into core-collapse supernovae.

This Tumblr’s Hubble week ends with the remnant of Supernova 1987A, photographed from 1994 to 2008 (at 656 or 658nm wavelengths).  In 2001, the ejecta from the supernova started colliding with the clumps of matter forming the smallest ring around the old star, causing the ring to get much brighter.  It’s interesting to watch it happen: some of those clumps must have been a little bit closer to the star than others, since the ring doesn’t all “light up” at once.

[Frames: Proposal ID 5203, 3 Feb 1994; Proposal ID 5753, 24 Sep 1994; Proposal ID 6020, 6 Feb 1996; Proposal ID 6437, 10 Jul 1997; Proposal ID 7434, 8 Jan 1999; Proposal ID 8243, 2 Feb 2000; Proposal ID 8648, 23 Mar 2001; Proposal ID 9114, 7 Dec 2001; Proposal ID 9114, 10 May 2002; Proposal ID 9428, 5 Jan 2003; Proposal ID 9992, 28 Nov 2003; Proposal ID 10263, 15 Dec 2004; Proposal ID 10549, 19 Nov 2005; Proposal ID 10867, 9 Dec 2006; Proposal ID 11181, 19 Feb 2008.]

The Mysterious Rings of Supernova 1987A 
Image Credit: ESA/HubbleNASA

Explanation: What’s causing those odd rings in supernova 1987A? Twenty five years ago, in 1987, the brightest supernova in recent history was seen in the Large Magellanic Clouds. At the center of the above picture is an object central to the remains of the violent stellar explosion. Surrounding the center are curious outer rings appearing as a flattened figure 8. Although large telescopes including the Hubble Space Telescope monitor the curious rings every few years, their origin remains a mystery. Pictured above is a Hubble image of the SN1987A remnant taken last year. Speculation into the cause of the rings includes beamed jets emanating from an otherwise hidden neutron star left over from the supernova, and the interaction of the wind from the progenitor star with gas released before the explosion.

Radioactive decay of titanium powers supernova remnant by europeanspaceagency on Flickr.

Via Flickr:
Supernova remnant SNR1987A is located 166 000 light-years away in the Large Magellanic Cloud. The light from the stellar explosion arrived at Earth in 1987, and has since provided astronomers with a natural laboratory to monitor how the brightness of a supernova changes over time.

Dominating this Hubble Space Telescope view of the remnant are two glowing loops and a very bright ring of shocked hotspots surrounding the location of the now-exploded central star. The material making up these loops and rings was probably ejected from the star earlier in its history and is now being illuminated by the supernova and its shockwave.

The titanium-44 detected by Integral is powering only the innermost part of the remnant.

Astronomers expect a neutron star to have been left after the explosion, but no definitive evidence for it has yet been found.

The field of view is about 25 x 25 arcseconds.

For more information, please click here.

Credits: ESA/Hubble & NASA

SN 1987A

In mid-September, NuSTAR obtained deep observations of SN 1987A one of the brightest stellar explosions since Galileo first pointed a telescope into the night sky more than 400 years ago. The supernova was first seen in February 1987, and has been extensively studied ever since. Pictured here is an image obtained with the High Resoluton Channel of the Hubble Space Telescope’s Advanced Camera for Surveys. NuSTAR, detecting high-energy X-rays emitted by the explosion remnants, has much lower resolution than Hubble, but provides important and unique additional information.

The supernova belongs to the Large Magellanic Cloud, a dwarf companion galaxy to our own Milky Way Galaxy, only 168,000 light-years away. SN 1987A is an example of a “core collapse” supernova, meaning it resulted from the death throes of a young, isolated, extremely massive star. With NuSTAR, we hope to detect 44-Ti emission from the SN 1987A explosion remnant, which is an important diagnostic of the explosion physics.

Image credit: NASA/Hubble
Exploded Star's Guts Shining Bright Again, Photo Shows

“The glowing entrails of an exploding star, thought to have faded over time, now appear to be lighting up again, a new Hubble Space Telescope photo reveals.  NASA released the new Hubble image of the well-known star explosion, called Supernova 1987A, today (June 10). The photo shows the closest supernova explosion witnessed in almost 400 years. This has allowed astronomers to study it in unprecedented detail as the outburst evolves.”

About 165,000 years ago, a massive star in a small galaxy called the Large Magellanic Cloud (LMC), orbiting the Milky Way distantly, was in its death throes.  After a few million years of furiously burning hydrogen and releasing the resulting energy as heat and light, its hydrogen fuel burned out.  It began burning the helium that was effectively the “ashes” of the hydrogen burning phase; this too was soon exhausted.  The ashes of each successive fusion cycle became the fuel for the next as the nuclear reactions raced up the periodic table, until all that was left was iron.  Iron is unusual, however, in that rather than releasing energy in nuclear reactions, it actually absorbs it.  In a matter of seconds as the iron built up, the star’s core was robbed of the energy needed to support it against the gravitational crush of overlying layers of material.  After existing in a state of physical equilibrium for millions of years, with the energy of nuclear fusion pushing back against gravity, the power source was gone.  The outer layers of the supergiant stat collapsed onto the Earth-sized ball of iron at the center of the star; as the density of this material quickly increased, those outer layers rebounded outward, suddenly destroying the star.

The news took thousands of years to travel the distance to Earth.  On the morning of 24 February 1987, it was heralded by the unexpected arrival of neutrinos, detected in laboratories around the world.  The nearly massless particles produced in the catastrophe of the core collapse of the star raced out at the speed of light, while the light and radiation of the ensuing explosion were optically “trapped” in the expanding shell of debris.  A few hours later, a brilliant “new” star appeared toward the LMC, the brightest supernova to be seen from Earth in 400 years.  Called “SN 1987A” (“supernova 1987A”, as it was the first supernova discovered in 1987), it is the youngest supernova remnant (SNR) we know of, and a virtually unique laboratory for everything from high energy physics to the astrophysics of nuclear reactions.  Three years after the light from 1987A arrived at the Earth, the Hubble Space Telescope was launched and it later began monitoring the changing effects of the debris shell as it plowed into the interstellar space around where the star once shone.  Nearly 20 years of data show an amazing view, never before seen, as a dying star literally reconfigures the contents of the space around it.

New observations from Chandra, an X-ray-sensitive cousin of Hubble,  show that after having faded for a while after initially encountering a ring of material probably blown off in successive bubbles from the dying progenitor star, the light from the explosion faded.  But it is brightening again.  A new paper, to appear in the Astrophysical Journal Letters by Park et al. suggests that the shock front moving outward from the explosion, after having encountered an increasing density of interstellar material for the first 20+ years after the explosion, is now propagating into a region of decreasing density, so less of its mechanical energy is going into compressing and heating up the interstellar material.  They surmise that the material through which the shock wave is plowing might have been blown out into space by the progenitor star itself near the end of its life when it went through what is called a Luminous Blue Variable phase.  (These objects are also called Wolf-Rayet stars.)  Sometimes their intense ultraviolet energy lights up the material, causing it to glow like in the nebula NGC 6888:

Note that the star in the middle is significantly bluer than the ones around it – that’s the Wolf-Rayet star.  The pinkish light comes from excited hydrogen atoms that were once part of its outer atmosphere.  But the progenitor of SN 1987A didn’t show a nebula like this; we know because the star before the explosion was identified on old photographic plates, giving vital information about it’s pre-supernova properties.  So the mystery is certainly far from solved.

Astronomy is very much now moving into the “time domain”, in which observations in which time is the variable provide information to which we never had access previously.  Expect exciting discoveries in the coming decades as major new facilities come online designed to tap into this underutilized resource.

Hubble Sees a Star Set to Explode

Floating at the center of this new Hubble image is a lidless purple eye, staring back at us through space. This ethereal object, known officially as [SBW2007] 1 but sometimes nicknamed SBW1, is a nebula with a giant star at its center. The star was originally twenty times more massive than our sun, and is now encased in a swirling ring of purple gas, the remains of the distant era when it cast off its outer layers via violent pulsations and winds.

But the star is not just any star; scientists say that it is destined to go supernova. Twenty-six years ago, another star with striking similarities went supernova — SN 1987A. Early Hubble images of SN 1987A show eerie similarities to SBW1. Both stars had identical rings of the same size and age, which were travelling at similar speeds; both were located in similar HII regions; and they had the same brightness. In this way SBW1 is a snapshot of SN1987a’s appearance before it exploded, and unsurprisingly, astronomers love studying them together.

At a distance of more than 20 000 light-years it will be safe to watch when the supernova goes off. If we are very lucky it may happen in our own lifetimes.

Credit: ESA/NASA, acknowledgement: Nick Rose.

SN 1987a in the Large Magellanic Cloud

Glittering stars and wisps of gas create a breathtaking backdrop for the self-destruction of a massive star, called supernova 1987A, in the Large Magellanic Cloud, a nearby galaxy. Astronomers in the Southern hemisphere witnessed the brilliant explosion of this star on Feb. 23, 1987. Shown in this NASA/ESA Hubble Space Telescope image, the supernova remnant, surrounded by inner and outer rings of material, is set in a forest of ethereal, diffuse clouds of gas.

Image credit: Hubble Heritage Team (AURA/STScI/NASA/ESA

From Astronomy Picture Of The Day; February 27, 2012:

Shocked by Supernova 1987A 
Hubble Space TelescopeNASAESA; Video compilation: Mark McDonald

Twenty five years ago, the brightest supernova of modern times was sighted. Over time, astronomers have watched and waited for the expanding debris from this tremendous stellar explosion to crash into previously expelled material. A clear result of such a collision is demonstrated in the above time lapse video of images recorded by the Hubble Space Telescope between 1994 and 2009. The movie depicts the collision of an outward moving blast wave with the pre-existing, light-year wide ring. The collision occurred at speeds near 60 million kilometers per hour and shock-heats the ring material causing it to glow. Astronomers continue to study the collision as it illuminates the interesting past of SN 1987A, and provides clues to the origin of the mysterious rings.

Star Death in 3-D

Image courtesy ESO

The hourglass shape of the supernova remnant SN 1987A isn’t as well balanced as thought, according to an August picture of the exploded star.

Using data on the remnant from the European Southern Observatory’s Very Large Telescope in Chile, astronomers were able to confirm that, when massive stars explode, some of the ejected material gets shot into space faster than other debris, as predicted by computer models.

Physicist suggests speed of light might be slower than thought

Physicist James Franson of the University of Maryland has captured the attention of the physics community by posting an article to the peer-reviewed New Journal of Physics in which he claims to have found evidence that suggests the speed of light as described by the theory of general relativity, is actually slower than has been thought.

The theory of general relativity suggests that light travels at a constant speed of 299,792,458 meters per second in a vacuum. It’s the c in Einstein’s famous equation after all, and virtually everything measured in the cosmos is based on it—in short, it’s pretty important. But, what if it’s wrong?

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From Astronomy Picture Of The Day; February 26, 2012:

The Mysterious Rings of Supernova 1987A 

What’s causing those odd rings in supernova 1987A? Twenty five years ago, in 1987, the brightest supernova in recent history was seen in the Large Magellanic Clouds. At the center of the above picture is an object central to the remains of the violent stellar explosion. Surrounding the center are curious outer rings appearing as a flattened figure 8. Although large telescopes including the Hubble Space Telescope monitor the curious rings every few years, their origin remains a mystery. Pictured above is a Hubble image of the SN1987A remnant taken last year. Speculation into the cause of the rings includes beamed jets emanating from an otherwise hidden neutron star left over from the supernova, and the interaction of the wind from the progenitor star with gas released before the explosion.

NASA’s Hubble Sees A New Supernova Remnant Light Up by NASA Goddard Photo and Video on Flickr.

Via Flickr:
NASA image release June 10, 2011

Astronomers using NASA’s Hubble Space Telescope are witnessing the unprecedented transition of a supernova to a supernova remnant, where light from an exploding star in a neighboring galaxy, the Large Magellanic Cloud, reached Earth in February 1987. Named Supernova 1987A, it was the closest supernova explosion witnessed in almost 400 years.

The supernova’s close proximity to Earth has allowed astronomers to study it in detail as it evolves. Now, the supernova debris, which has faded over the years, is brightening. This means that a different power source has begun to light the debris.

The debris of SN 1987A is beginning to impact the surrounding ring, creating powerful shock waves that generate X-rays observed with NASA’s Chandra X-ray Observatory. Those X-rays are illuminating the supernova debris and shock heating is making it glow in visible light. The results are being reported in the June 9, 2011, issue of the journal Nature by a team including Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics (CfA), who leads a long-term study of SN 1987A with Hubble.

Since its launch in 1990, the Hubble telescope has provided a continuous record of the changes in SN 1987A.

Credit: NASA, ESA, and P. Challis (Harvard-Smithsonian Center for Astrophysics)

NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.

30 Supernovas Per Second in the Universe

While there is, on average, only one supernova per galaxy per century, there is something on the order of 100 billion galaxies in the observable Universe. Taking 10 billion years for the age of the Universe (it’s actually 13.7 billion, but stars didn’t form for the first few hundred million), Dr. Richard Mushotzky of the NASA Goddard Space Flight Center, derived a figure of 1 billion supernovae per year, or 30 supernovae per second in the observable Universe.

Supernovava 1987A, discovered in 1987, is the closest exploding star to Earth to be detected since 1604 and resides in the nearby Large Magellanic Cloud, a dwarf galaxy adjacent to our own Milky Way Galaxy. In addition to ejecting massive amounts of hydrogen, 1987A has spewed helium, oxygen, nitrogen and rarer heavy elements like sulfur, silicon and iron.

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