Tag Archives: supernova

Astronomers successfully predict appearance of supernova

For the first time ever astronomers have been able to predict and photograph the appearance of a supernova, its light focused by the gravitational lensing caused by a galaxy and the dark matter that surrounds it.

The NASA/ESA Hubble Space Telescope has captured the image of the first-ever predicted supernova explosion. The reappearance of the Refsdal supernova was calculated from different models of the galaxy cluster whose immense gravity is warping the supernova’s light.

What makes this significant is that the prediction models were based on the theory of gravitational lensing and required the presence of dark matter to work. That they worked and were successful in predicting the appearance of this gravitationally bent light (bent by the dark matter it passed through) is a very strong confirmation of both concepts. Up until now I have been somewhat skeptical of gravitational lensing. This confirmation removes some of that skepticism.

The supernova of 1987 finally begins to fade

Almost thirty years after Supernova 1987a became the first naked eye supernova since the invention of the telescope, the necklace ring of spots that the explosion’s shockwave ignited in the late 1990s are finally beginning to fade.

But now the hotspots have slowly begun to fade, Claes Fransson (Stockholm University, Sweden) and colleagues report in the June 10th Astrophysical Journal Letters. The team studied images taken by the Hubble Space Telescope from 1994 to 2014, and spectra from the Very Large Telescope spanning 2000 to 2013. Based on the rate at which the hotspots are fading, the researchers predict the glittering necklace will fade away sometime between 2020 and 2030, with the calculations favoring closer to 2020. The clumps of gas in the central ring are likely dissolving, thanks to a combination of instabilities and conduction in the hot gas surrounding the clumps. In other words, the central ring is being destroyed.

The show really isn’t over. The aftermath of a star exploding goes on for thousands of years. So to will SN1987a’s show.

Hubble finds something astronomers can’t explain

The uncertainty of science: The Hubble Space Telescope has spotted the explosion of a star that does not fit into any theory for stellar evolution.

The exploding star, which was seen in the constellation Eridanus, faded over two weeks — much too rapidly to qualify as a supernova. The outburst was also about ten times fainter than most supernovae, explosions that destroy some or all of a star. But it was about 100 times brighter than an ordinary nova, which is a type of surface explosion that leaves a star intact. “The combination of properties is puzzling,” says Mario Livio, an astrophysicist at the Space Telescope Science Institute in Baltimore, Maryland. “I thought about a number of possibilities, but each of them fails” to account for all characteristics of the outburst, he adds.

We can put this discovery on the bottom of a very long list of similar discoveries by Hubble, which this week is celebrating the 25th anniversary of its launch.

On that note, as part of that celebration Space.com today has published a long interview with me about Hubble and my book, The Universe in a Mirror, the saga of the Hubble Space Telescope and the visionaries who built it. They have also published an excerpt from the book. Check both out.

For more information about that newly discovered supernova in the nearby galaxy M82 go here and here.

For more information about that newly discovered supernova in the nearby galaxy M82 go here and here.

The first link notes that the supernova has brightened to 11.5 magnitude and could get even brighter in the next two weeks. Though still too dim for the naked eye, it is easily bright enough right now for most amateur telescopes and binoculars. How much brighter it will get remains a question.

Astronomers have identified a star they expect to go supernova very soon.

Astronomers have identified a star they expect to go supernova very soon.

[SBW2007] 1 (or SBW1) is located 20,000 light-years from Earth and features an enigmatic double-ringed planetary nebula. The rings are gases that have been blasted from the outermost layers of the blue supergiant star in the nebula’s core. The star, which was estimated to be 20 times the mass of the sun before it became unstable, is going through its final death throes before a supernova is initiated. But don’t worry, the supernova would be a safe distance from us, although it will put on an exciting light show.

There is no way to predict when the supernova will occur. On the timescales of stellar evolution, it could happen tomorrow, or in a thousand years. For the full Hubble image go here.

This story is significant in that it shows how much knowledge has been gained in astronomy since Hubble’s launch. In 1987, when Supernova 1987a exploded in the Large Magellanic Cloud, astronomers had not identified even one progenitor of any supernova, and did not have any clear idea what kinds of stars produced these gigantic explosions. Today, they have identified more than a handful, and are even beginning to pinpoint candidates, such as the star above, that could be the next stars to go boom.

The remarkable remains of a most recent supernova.

The remarkable remains of a most recent supernova.

Astronomers estimate that a star explodes as a supernova in our Galaxy, on average, about twice per century. In 2008, a team of scientists announced they discovered the remains of a supernova that is the most recent, in Earth’s time frame, known to have occurred in the Milky Way. The explosion would have been visible from Earth a little more than a hundred years ago if it had not been heavily obscured by dust and gas. Its likely location is about 28,000 light years from Earth near the center of the Milky Way.

A star has gone supernova and astronomers get to see it from the very beginning, and even earlier!

A star has gone supernova and astronomers get to see it from the very beginning, and even earlier!

The star had erupted several times before but had not produced a real supernova explosion. On September 26 it finally did so. Moreover, astronomers have images of the star prior to any eruption, information that until recently was not available for any supernovae.

Have astronomers found a future supernova?

A press release from the Carnegie Institute today described a recent paper by astronomers that might have identified a star in the Milky Way that might go supernova sometime in the future. The star QU Carinae, is a cataclysmic variable, a binary system in which material dumped from one star onto another periodically causes an outburst of X-rays.

I emailed Stella Kafka, the lead scientist of the research paper, to find out how far away QU Carinae is and how soon it might go supernova. She responded as follows:
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A supernova twenty-five years later.

A supernova twenty-five years later.

SN 1987A, it turns out, was like a dust-bomb, with estimates of the total dust it threw into space, based on the infrared brightness of the dust … implying enough dusty material to build the equivalent of 200,000 Earth-mass planets. Mingled within the dust are elements as diverse as oxygen, nitrogen, sulphur, silicon, carbon and iron. This immense amount of dust has been beyond expectations and, if all supernovae spew out this much dust, it helps explain why young galaxies that we can see existing in the early Universe, which have high rates or star birth and death, are so dusty. The dust, however, isn’t a nuisance to be wiped away – this is the material that goes into building new planets, moons and even life. The iron in your blood and the calcium in your bones all came from supernovae like SN 1987A, as mostly did the oxygen we breath and the carbon in our constituent molecules.

The last remant of a supernova

Time for some astronomical sightseeing! This image, produced from data taken by both the Hubble Space Telescope and the Chandra X-ray Observatory, shows what astronomers call a supernova remnant. The bubble, located in the Large Magellanic Cloud 160 thousand light years away, is thought to be 23 light years across and expanding about 11 million miles per hour. It is thought that the supernova itself took place around 1600. That we have no record of it is probably because it was only visible in the southern hemisphere, where few records of such events were being kept at that time. More here, including the image using only Hubble data as well as a video animation that is quite stunning.

Supernova remnant