Tag: supernova

Unprecedented Image Of A Supernova 80 Million Light Years Away Is Captured For The First Time By An Amateur Astronomer

The first burst of light given off by an exploding star has been captured for the first time by an amateur astronomer in Argentina.

Observations of a dying star 80 million light-years away, taken by Víctor Buso, 60, has given scientists their first view of the initial flash given off by a supernova.

To date, no one has been able to capture the ‘first optical light’ from a supernova, since stars explode seemingly at random in the sky, and the burst is fleeting.

Most are only spotted a long time after the initial blast, making Mr Buso’s one-in-ten-million observations ‘unprecedented‘, scientists said.

The new data provide important clues to the physical structure of the star just before its catastrophic demise and to the nature of the explosion itself.

Professional astronomers have long been searching for such an event,” said University of California at Berkeley astronomer Dr Alex Filippenko, who followed up the lucky discovery with scientific observations of the explosion, called SN 2016gkg.




Observations of stars in the first moments they begin exploding provide information that cannot be directly obtained in any other way.”

It’s like winning the cosmic lottery.”

During tests of a new camera, Mr. Buso snapped images through his 16-inch telescope of the galaxy NGC 613, which is 80 million light-years from Earth.

He took a series of short-exposure photographs of the spiral galaxy, accidentally capturing it before and after the supernova’s ‘shock breakout’.

This is when a pressure wave from the star’s exploding core hits and heats gas at the star’s surface to a very high temperature, causing it to flash and rapidly brighten.

Upon examining the images, Mr. Buso, of Rosario, Argentina, noticed a faint point of light quickly brightening near the end of a spiral arm that was visible in his second set of images but not his first.

Astronomer Dr Melina Bersten and her colleagues at the Instituto de Astrofísica de La Plata in Argentina soon learned of the serendipitous discovery.

They realized that Mr. Buso had caught a rare event; part of the first hour after light emerges from a massive exploding star.

She estimated Mr Buso’s chances of such a discovery, his first supernova, at one in 10 million or perhaps even as low as one in 100 million.

Dr Bersten contacted an international group of astronomers to help conduct additional frequent observations of SN 2016gkg.

A series of subsequent studies have revealed more about the type of star that exploded and the nature of the explosion.

Mr. Buso’s discovery, snapped in September 2016, and results of follow-up observations have now been published in the journal Nature.

Buso’s data are exceptional,” Dr. Filippenko added.

This is an outstanding example of a partnership between amateur and professional astronomers.

The astronomer and his colleagues obtained a series of seven spectra, where the light is broken up into its component colors, as in a rainbow.

They used the Shane 3-meter telescope at the University of California’s Lick Observatory near San Jose, California, and the twin 10-meter telescopes of the W. M. Keck Observatory on Maunakea, Hawaii.

This allowed the international team to determine that the explosion was a Type IIb supernova: The explosion of a massive star that had previously lost most of its hydrogen envelope.

Combining the data with theoretical models, the team estimated that the initial mass of the star was about 20 times the mass of our Sun.

They suggest it lost most of its mass to a companion star and slimmed down to about five solar masses prior to exploding.

Further analyses of the signal could provide further information on the star’s structure and uncover more secrets about supernovas.

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Pass it on: Popular Science

Mystery Of The Zombie Star That Won’t Die

A brightly burning ‘zombie‘ supernova that refuses to die has left astronomers baffled.

The star, which lies half a billion light years away, has exploded numerous times since 1954.

This has stumped astronomers as supernovas are generally considered to explode just once and standard theoretical models cannot explain its behaviour.

Researchers at Las Cumbres Observatory in Goleta, California, have been studying the phenomenon, which was first observed in 2014 by the Intermediate Palomar Transient Factory telescope near San Diego.

In January 2015 the event, known as iPTF14hls, was classified as a type II-P supernova, which results from the rapid collapse and violent explosion of a single massive star.




This type of supernova gives off a distinctive flash and tend to stay bright for around 100 days and supernovae lasting more than 130 days are extremely rare.

But iPTF14hls remained bright for almost two years (600 days), with the brightness of the light it emitted varying by up to 50 per cent over this time, as if it were exploding over and over again.

The evolution of the event also seems to be taking place roughly ten times slower than others of its type.

Adding to the puzzle, telescope imagery uncovered by the team suggests explosions may have taken place at the same location in 1954.

Supernovae are known to explode only once, shine for a few months and then fade, but iPTF14hls experienced at least two explosions, 60 years apart.

Writing in an opinion piece for the journal Nature, Stan Woosley, a professor of astronomy at the University of California, Santa Cruz, said of the findings.

As of now, no detailed model has been published that can explain the observed emission and constant temperature of iPTF14hls, let alone the possible eruption 60 years before the supernova.

“A better understanding could provide insight into the evolution of the most massive stars, the production of the brightest supernovae and possibly the birth of black holes that have masses near 40 solar masses, such as those associated with the first direct detection of gravitational waves.”

“For now, the supernova offers astronomers their greatest thrill: something they do not understand.”

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Pass it on: New Scientist

‘The Strangest Supernova We’ve Ever Seen’: A Star That Keeps Exploding — And Surviving!

A supernova signals a star’s death throes. Having exhausted its fuel for nuclear fusion, the star collapses, producing a gigantic explosion of matter and energy that can be seen from 10 billion light-years away.

The supernova shines for a few months, then fades. All that remains after the cosmic light show is either a dense, smoldering core, called a neutron star, or a gaping black hole.

At least, that is what’s supposed to happen.

Some 500 million light-years away, in a galaxy so distant it looks like little more than a smudge, a star exploded five times over the course of nearly two years, spewing the contents of 50 Jupiters and emitting as much energy as 10 quintillion suns.

This isn’t even the first time this star has gone supernova: Astronomers believe this same body was seen exploding 60 years ago.




Somehow, this “zombie” star has managed to survive one of the most powerful, destructive events known to science — multiple times.

It should make us question, researchers wrote Wednesday in the journal Nature, how much we really know about supernovas.

The discovery was made by scientists working on the Intermediate Palomar Transient Factory, which uses a telescope near San Diego to survey the night sky for ephemeral events like supernovas.

Iair Arcavi, an astrophysicist at the University of California at Santa Barbara and Las Cumbres Observatory who worked on the project, was mainly interested in stars in the early stages of explosion.

So, in September 2014, when the survey captured a fading supernova near the constellation Ursa Major, he didn’t give it much thought. The event looked like a garden variety star well on its way toward oblivion.

Five months later, an intern who had been assigned to look over old data asked Arcavi to look at something weird.

The intern pulled up a plot of the supernova’s emissions over the past 137 days — bizarrely, the explosion was getting brighter.

Figuring that this must be a fluke — maybe just a star in our galaxy twinkling weirdly — Arcavi broke the light from the explosion into its component wavelengths. This “spectrum” contained all the signatures of a supernova.

Even stranger, it looked like a nova that was only 30 days old — though the scientists had concrete proof that it had in fact been going on for months.

The event, dubbed iPTF14hls, was put on 24/7 watch.

The eyes of the Las Cumbres Observatory — a robotic network of telescopes positioned all over the world — followed the supernova as it brightened, then faded, then brightened again.

The nova hit five peaks of brightness before finally seeming to dwindle in summer 2016. But at 600 days old, it was already the longest-lived supernova ever observed.

In an analysis for Nature, Stan Woosley of the University of California at Santa Cruz, who was not involved in the research, wrote that a better understanding of iPTF14hls could lead to revelations about the evolution of massive stars.

The emergence of extremely bright supernovas and, maybe, the origins of the kind of black holes we’ve detected with gravitational waves.

For now,” he concluded, “the supernova offers astronomers their greatest thrill: something they do not understand.

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Astronomers Solve Mystery Of ‘New Star’ Spotted In 1437 AD

On a spring night in 1437 AD, something unusual happened — Korean astronomers spotted a new star in the sky above Seoul. Two weeks later, they reported, it vanished again.

Now scientists have finally tracked down the object behind that temporary sparkle in the sky, offering a new glimpse into the hidden lives of stars, and how they evolve through different stages of their lives.

The new star was a nova (a word that literally means new star) or stellar eruption that appeared in the tail of the constellation known in the western world as Scorpio.

Canadian astronomer Michael Shara began looking for the source of the ancient nova more than 30 years ago. He has finally found it, he reports in a paper published Wednesday in the journal Nature.

Shara, an astrophysics curator at the American Museum of Natural History who was born and raised in Montreal, became interested in the story of the mysterious Korean star back in 1986.




The fact that it appeared and then disappeared in 14 days suggested it was a classical nova, sudden brightening of a star that isn’t as intense or long lasting as a supernova or star explosion.

What excited Shara was the Korean astronomers had provided a lot of details that should allow astronomers to figure exactly where in the sky that nova had appeared.

It was spotted above Seoul on March 11, 1437, they reported, between the second and third star of a part of the sky that eastern astronomers call the sixth lunar mansion. That would have been very near the horizon.

The problem was, Shara said, “there’s no good map from the Koreans which points at the sky or shows you the constellations and tells you which is second star and which is the third.

Historian help

Shara enlisted the help of Richard Stephenson, a historian of ancient Asian astronomical records at Durham University in England.

By looking at Chinese maps, which also divide the sky into lunar mansions, Stephenson managed to pinpoint where he thought the star that caused the nova should be located.

For decades, on and off, Shara, Stephenson and other collaborators used telescopes around the world to search the area that Stephenson pointpointed.

It became a bit of an obsession,” he admitted.

Then about a year and a half ago, after a long break, he decided to try again. But this time, he widened his search area a little bit.

And in 90 minutes, I found it,” he recalled. “It was the moment both of exaltation and a little bit of, ‘Oh my God, all that wasted time and effort!’

It turns out the star wasn’t where it was expected because it had “moved” over the past 580 years, owing to the fact the star is relatively close by — just a few hundred light years away — compared to most other stars in the sky.

So it appears to move more quickly, just as nearby objects go by more quickly than those that are farther away when you look out the window of a moving car.

That inconvenient quirk made it hard to find the star, but now represents a new way to measure time in astronomy, Shara said. “That’s a cool thing.

Butterflies and caterpillars

But an even more exciting discovery was what got Shara interested in the star in the first place — he thought it could help him observe the way certain stars evolve through different stages of their life cycle.

It would help prove his theory that two types of binary stars — systems of two stars that orbit each other — were actually two different life stages of the same star.

They’re like butterflies and caterpillars,” he told CBC News. But while caterpillars turn into butterflies within weeks, stars transform very slowly.

Often, even very “fast” changes would take hundreds of years to observe, so you would have to compare a star today to what it looked like hundreds of years ago.

That’s what Shara did.

Sure enough, the data seemed to show what he predicted.

A nova like the one spotted by the Korean astronomers is typically caused by a binary star consisting of a white dwarf and a younger, active star such as a red dwarf.

A white dwarf is a tiny, dense dead star, while a red dwarf is a star similar to our own sun, but a little bit smaller and cooler.

A nova comes from a nuclear eruption from the surface of the white dwarf “in kind of a giant hydrogen bomb,” Shara said. The eruption throws a giant shell or nebula of material from the surface into space.

It also heats everything up into a “nova-like binary star,” an object that glows 100 to 1000 times as bright as the sun for hundreds of years, Shara said.

Shara had predicted that nova-like binary stars eventually cool down and become much dimmer objects called dwarf novas, which brighten to a tenth the brightness of the sun every few months.

But no one had ever observed that — until now.

By looking at images over the past century of the star that caused the 1437 nova, Shara spotted the shell thrown off by the eruption and multiple dwarf novas.

Interestingly, Shara likely first spotted the shell at the beginning of his search in the 1980s, when  he was searching with University of Montreal astronomer Anthony Moffat at an Australian telescope.

And we saw, ‘Oh, there’s a smudge — that could be the nova,'” recalled Moffat, who co-authored the paper.

But the star, which later turned out to have moved more than the shell, was nowhere to be found.

Moffat finally heard the news about the discovery of the star itself last year.

I couldn’t believe it,” he said, “after all these years.

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Pass it on: Popular Science

Speedy White Dwarf Fragment Might Have Survived A Partial Supernova

Astronomers have discovered a star like none seen before. They think it may be the remnant of an incomplete supernova explosion, something that would explain one mystery, but create enough new ones to keep them happily hunting for a long time.

LP 40-365 is a 15th magnitude star, making it far too faint to see with the naked eye, but much brighter than the vast majority of objects recorded in sky maps.




Catalogs of stars registered the fact that it appears to be traveling very rapidly compared to the rest of the galaxy, and interested by such speedster stars, Professor Lilia Ferrario of the Australian National University and some fellow astronomers decided to check it out.

What they found, Ferrario told IFLScience, was more fascinating than anyone expected. LP 40-365’s light spectrum clearly marks it as a white dwarf, but one smaller than any we have seen before – just 0.14 times the mass of the Sun.

White dwarfs are extremely compact stars, where gravitational collapse is prevented by the pressure exerted by a gas of degenerate electrons. A teaspoon of white dwarf material would weigh many tonnes on Earth,” Ferrario said in a statement.

White dwarfs are the remnants of medium to large stars that have run out of fuel. They are called dwarfs because they are very compact, but, even with all the material they have lost, their masses are close to that of the Sun.

LP 40-365 “must have interacted with something to end up the way it is,” Ferrario told IFLScience.

The explanation Ferrario and her colleagues have presented in Science is that LP 40-365 is the result of what is called a Iax supernova.

Type Ia supernovas are thought to occur when a white dwarf star that is part of a binary system with another star draws gas away from its companion until it has so much it explodes, although a subclass is triggered by the collision of two white dwarfs.

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Pass it on: New Scientist