supernova Archives

October 30, 2014December 23, 2015 by Bob King

Possible Bright Supernova Lights Up Spiral Galaxy M61

An animation showing a comparison between the confirmation image (at top) and an archive photo. Credit: Ernesto Guido, Martino Nicolini, Nick Howes

I sat straight up in my seat when I learned of the discovery of a possible new supernova in the bright Virgo galaxy M61. Since bright usually means close, this newly exploding star may soon become visible in smaller telescopes. It was discovered at magnitude +13.6 on October 29th by Koichi Itagaki of Japan, a prolific hunter of supernovae with 94 discoveries or co-discoveries to his credit. Itagaki used a CCD camera and 19.6-inch (0.50-m) reflector to spy the new star within one of the galaxy’s prominent spiral arms. Comparison with earlier photos showed no star at the position. Itagaki also nabbed not one but two earlier supernovae in M61 in December 2008 and November 2006.

The possible supernova in the bright galaxy M61 in Virgo is located 40" east and 7" south of the galaxy's core at right ascension (RA) 12 h 22', declination (Dec) +4º 28' It's currently magnitude +13.4 and visible in the morning sky before dawn in 8-inch and larger telescopes. Credit: Ernesto Guido, Martino Nicolini, Nick Howes — The possible supernova in the bright galaxy M61 in Virgo is located 40″ east and 7″ south of the galaxy’s core at right ascension (RA) 12 h 22′, declination (Dec) +4º 28′. It’s currently magnitude +13.4 and visible in the morning sky before dawn in 8-inch and larger telescopes. Credit: Ernesto Guido, Martino Nicolini, Nick Howes

Overnight, Ernesto Guido and crew used a remote telescope in New Mexico to confirm the new object. We’re still waiting for a spectrum to be absolutely sure this is the real deal and also to determine what type of explosion occurred. In the meantime, it may well brighten in the coming mornings.

M61 is a beautiful barred spiral galaxy located about 55 million light years from Earth in the constellation Virgo. It's one of the few galaxies to show spiral structure in smaller telescopes. Credit: Hunter Wilson — M61 is a beautiful barred spiral galaxy located about 55 million light years from Earth in the constellation Virgo. It’s one of the few galaxies to show spiral structure in smaller telescopes. Credit: Hunter Wilson

Supernovae are divided into two broad categories – Type Ia and Type II. In a Type Ia event, a planet-sized white dwarf star in close orbit around a normal star siphons off matter from its companion which builds up on the surface of the dwarf until it reaches critical mass at which point the core ignites and consumes itself and the star in one titanic nuclear fusion reaction. A cataclysmic explosion ensues as the star self-destructs in blaze of glory.

Evolution of a Type Ia supernova. Credit: NASA/ESA/A. Feild

Type Ia explosions can become 5 billion times brighter than the Sun – the reason we can see them across so many light years – and eject matter into space at 5,000 – 20,000 km/second. Type II events mark the end of the life of a massive supergiant star. As these behemoths age, they burn by fusing heavier and heavier elements in their cores from hydrogen to carbon to silicon and finally, iron-nickel. Iron is inert and can’t be cooked or fused to create more energy. The star’s internal heat source, which has been staving back the force of gravity all these millions of years, shuts down. Gravity takes hold with a vengeance, the star quickly collapses then rebounds in a titanic explosion. Ka-boom!

Artist's impression of a Type II supernova explosion which involves the destruction of a massive supergiant star. Credit: ESO — Artist’s impression of a Type II supernova explosion which involves the destruction of a massive supergiant star. Credit: ESO

Like the Type Ia event, a Type II supernova grows to fantastic brilliance. Besides a legacy of radiant light, star debris, the creation of heavy elements like gold and lead, a Type II event will sometimes leave behind a tiny, city-sized, rapidly-spinning neutron star – the much compressed core of the original star – or even a black hole. So yes, life can continue for a giant star after a supernova event. But like seeing a former classmate at your 40th high school reunion, you’d hardly recognize it.

The "Y" or cup of Virgo rises into good view shortly before the start of dawn or about 2 hours before sunrise. This map shows the sky facing east around 6 a.m. local time (DST) and 5 a.m. starting Sunday when Daylight Saving Time is done. Source: Stellarium — The “Y” or “cup” of Virgo rises into good view shortly before the start of dawn or about 2 hours before sunrise. This map shows the sky facing east around 6 a.m. local time (DST) tomorrow October 31 and 5 a.m. standard time starting Sunday when Daylight Saving Time ends. Source: Stellarium

Are you itching to see this new supernova for yourself? Here are a couple maps to help you find it. M61 is located in the middle of the “Y” of Virgo not far from the familiar bright double star Gamma Virginis. From many locations, the galaxy climbs to 15-20° altitude in the east-southeast sky just before the start of dawn, just high enough for a good view. Once you find the galaxy, look for a small “star” superimposed on its eastern spiral arm as shown in the photo at the top of this article.

In this close up view, stars are shown to magnitude +7.5. M61 is right between 16 and 17 Virginis (magnitudes 5 and 6.5 respectively). Source: Stellarium — In this close up view, stars are shown to magnitude +7.5. M61 is right between 16 and 17 Virginis (magnitudes 5 and 6.5 respectively). Click to enlarge. Source: Stellarium

I’ll be out there with my scope watching and will report back once it’s established what type of supernova happens to be blowing up in our eyepieces. More information about the new object can be found anytime at David Bishop’s Latest Supernovae site. Good luck, clear skies!

** Update Nov. 1 : M61’s supernova now has a name and type! SN 2014dt is a Type Ia (exploding white dwarf) with some peculiarities in its spectrum. It’s also little brighter at magnitude +13.2.

October 7, 2014December 23, 2015 by Elizabeth Howell

How to Turn Your Phone Into A Cosmic Ray Detector

Artist's impression of cosmic rays striking Earth (Simon Swordy/University of Chicago, NASA)

Quick, do you have an Android phone in your pocket? A few small changes and you could help physicists probe more of the curious nature of cosmic rays, high-energy particles that emanate from outside our solar system.

Just download an app, cover up your phone’s camera with duct tape, then place it somewhere (running idle) with the screen facing up. If a particle “event” happens, the information will be logged in a central database.

The project (called Distributed Electronic Cosmic-ray Observatory or DECO) aims to record secondary particles called muons that occur when cosmic rays hit the Earth’s atmosphere. Scientists believe cosmic rays are created in black holes and supernovas, but more studies are needed.

Screenshot of an Android app developed at the University of Wisconsin-Madison that aims to capture cosmic rays. Credit: Justin Vandenbroucke

Researchers at the Wisconsin IceCube Particle Astrophysics Center (WIPAC), led by Justin Vandenbroucke, note that there are things about cosmic rays that confuse physicists. Their paths in space change as they go across magnetic fields, and it makes searching for other astronomy events difficult. That’s where they hope the phone study will be useful.

“Smartphone cameras use silicon chips that work through what is called the photoelectric effect, in which particles of light, or photons, hit a silicon surface and release an electric charge,” the University of Wisconsin-Madison wrote in a press release.

“The same is true for muons. When a muon strikes the semiconductor that underpins a smartphone camera, it liberates an electric charge and creates a signature in pixels that can be logged, stored and analyzed.”

For more details on how to run and use the app, consult this page (it’s the second item).

Source: University of Wisconsin-Madison

September 11, 2014December 23, 2015 by Shannon Hall

A Lurking Companion Star Explains Enigmatic Supernova

The above sequence depicts a rare supernova explosion. The topic panel

Massive stars end their lives dramatically. Once the nuclear fuel deep within their cores is spent, there’s no longer any outward pressure to push against gravity, and the star collapses. But while the inner layers fall in to form a black hole or a neutron star, the outer layers fall faster, hitting the inner layers, and rebounding in a huge supernova explosion.

That’s the textbook definition. But some of these supernovae defy explanation. In 2011 one such explosion, dubbed SN 2011dh, pierced the Whirlpool galaxy, roughly 24 million-light years away. At the time astronomers were baffled. But now, thanks to NASA’s Hubble Space Telescope, they’ve discovered a companion star to this rare supernova and fit the final puzzle pieces together.

SN 2011dh is a Type IIb supernova, unusual in that it contains very little hydrogen and unexplainable via a textbook definition. Even so, astronomers can shed light on the progenitor star simply by digging through archived images from HST. Thanks to HST’s wealth of data and the fact that it observes the Whirlpool galaxy often, two independent research teams both detected a source — a yellow supergiant star — at the right location.

But astronomers don’t think yellow supergiant stars are capable of becoming supernovae … at least not in isolation.

At this point, controversy arose within the astronomical community. Several experts proposed that the observation was a false cosmic alignment and that the actual progenitor was an unseen massive star. Other experts proposed that the progenitor could have been the yellow supergiant, but that it must have belonged in a binary star system.

When a massive star in a binary system overflows its Roche lobe — the region outside that star where gravity dominates — it can pour material onto its smaller companion, therefore losing its hydrogen envelope and shrinking in mass.

At the time the mass-donor explodes, the companion star should be a massive blue star, having gained material during the mass transfer. Its high temperature should also cause it to emit mostly in the ultraviolet range, therefore rendering it invisible in any visible images.

So Gastón Folatelli from the Kavli Institute for the Physics and Mathematics of the Universe (IPMU) and colleagues decided to take a second look at the mysterious supernova in ultraviolet light. And their observations matched their expectations. The original supernova had faded, and a different point source had taken its place.

“One of the most exciting moments in my career as an astronomer was when I displayed the newly arrived HST images and saw the object right there, where we had anticipated it to be all along,” said Folatelli in a news release.

The research illustrates the intricate interplay between theory and observation. Astronomers often rely on theories long before they gain the technology necessary to provide the correct observations or spend years trying to explain odd observations with complex theoretical modeling. More often, however, the two coexist as theory and observation banter back and forth.

The findings have been published in the Astrophysical Journal Letters and are available online.

August 15, 2014December 23, 2015 by Elizabeth Howell

What Sparked Star Explosion 2014J? NASA Telescope Seeks Clues

Astronomers are gazing closely at supernova 2014J (inset) to see what sort of triggers caused the star explosion. Credit: NASA/SAO/CXC/R. Margutti et al

X marks the spot: after probing the area where a star used to be, in X-rays, astronomers have been able to rule out one cause for the supernova explosion.

Because the Chandra X-Ray Observatory did not detect anything unusual in X-rays, astronomers say this means that a white dwarf was not responsible for pulling off material from a massive star that exploded (from Earth’s vantage point) on Jan. 21, 2014, triggering excitement from professional and amateur astronomers alike.

“While it may sound a bit odd, we actually learned a great deal about this supernova by detecting absolutely nothing,” stated study leader Raffaella Margutti of the Harvard-Smithsonian Center for Astrophysics (CfA) in Massachusetts. “Now we can essentially rule out that the explosion was caused by a white dwarf continuously pulling material from a companion star.”

So what caused it? Possibly two white dwarfs merged instead. Follow-up observations will take place in Messier 88 and the source of the explosion, which was about 12 million light-years from Earth. While that’s a long time by human standards, astronomers point out that is close on the cosmic distance scale.

A study on this work was recently published in The Astrophysical Journal. You can read a preprint version of the article here.

Source: NASA

August 6, 2014December 23, 2015 by Shannon Hall

Hubble Archive Reveals Possible Culprit for Enigmatic Supernova

The white X at the top of the image marks the location of the supernova. The inset panel is a pair of Hubble Space Telescope images of the spiral galaxy NGC 1309 that were taken before and after the appearance of Supernova 2012Z. Credit: NASA, ESA, C. McCully and S. Jha (Rutgers University), R. Foley (University of Illinois), and Z. Levay (STScI)

More than two decades of Hubble observations have produced more than 25 terabytes of data. Thanks to the wealth of information stored in the Hubble data archive, astronomers can easily revisit old images in an effort to better understand new discoveries.

Now, astronomers have used the archive to find the progenitor of a mysterious type of supernova, dubbed Type 1ax, which is less energetic and much fainter than its Type Ia cousin.

A Type 1a supernova occurs when a white dwarf siphons material off a companion star, building an additional layer of hydrogen on its surface that will eventually trigger a runaway reaction that detonates the accumulated gas.

The most popular explanation for Type 1ax supernovae is that they’re created in the same way, except the explosion doesn’t completely tear the white dwarf into pieces. Instead, the white dwarf ejects roughly half of its mass. It becomes battered and bruised, leaving behind a hot core composed of carbon and oxygen.

So far, astronomers have identified more than 30 of these mini-explosions, which occur at one-fifth the rate of Type 1a supernovae.

“Astronomers have been searching for decades for the progenitors of Type Ia’s,” said Saurabh Jha from Rutgers University in a NASA press release. “Type Ia’s are important because they’re used to measure vast cosmic distances and the expansion of the universe. But we have very few constraints on how any white dwarf explodes. The similarities between Type Iax’s and normal Type Ia’s make understanding Type Iax progenitors important, especially because no Type Ia progenitor has been conclusively identified.”

So after the team observed the weak supernova, dubbed SN 2012Z, in the Lick Observatory Supernova Search, they dug through Hubble’s archive. Fortuitously, Hubble had observed the supernova’s host galaxy, NGC 1309, in 2005, 2006, and 2010, before the supernova outburst.

Curtis McCully, a graduate student at Rutgers and lead author on the team’s paper, reprocessed the pre-explosion images to find an object at the supernova’s position.

“I was very surprised to see anything at the supernova’s location,” said McCully. “We expected that the progenitor system would be too faint to see, like in previous searches for normal Type Ia supernova progenitors. It is exciting when nature surprises us.”

The pre-supernova observations reveal a bright, blue source the team calls S1. McCully and colleagues concluded that they were most likely seeing a star that had lost its outer hydrogen envelope, revealing its helium core. But they don’t think it’s a type of star that was about to explode, rather it’s the companion that fed the white dwarf’s outburst.

The most likely explanation involves a binary star system where each star detonates mass to the other over time.

The team acknowledges that they can’t totally rule out other possibilities for the object’s identity, including that it was simply a single, massive star that exploded as a supernova. To settle any uncertainties the team plans to use Hubble again in 2015. Hopefully by then the supernova should fade enough to get a better look at what remains.

The team’s results will appear in the journal Nature tomorrow.

July 22, 2014December 23, 2015 by Elizabeth Howell

Cosmic Fireworks: A Supernova Feast And Google+ Hangout For Chandra’s 15th Anniversary

A collection of images from the Chandra X-Ray Observatory marking its 15th anniversary in space. Top, from left: the crab Nebula, supernova remnant G292.0+1.8 and the Crab Nebula. At bottom, supernova remnant 3C58. Credit: NASA/CXC/SAO

It’s well past the Fourth of July, but you can still easily find fireworks in the sky if you look around. The Chandra X-Ray Observatory has been doing just that for the past 15 years, revealing what the universe looks like in these longer wavelengths that are invisible to human eyes.

Just in time for the birthday, NASA released four pictures that Chandra took of supernova (star explosion) remnants it has observed over the years. The pictures stand as a symbol of what the telescope has shown us so far.

“Chandra changed the way we do astronomy. It showed that precision observation of the X-rays from cosmic sources is critical to understanding what is going on,” stated Paul Hertz, NASA’s Astrophysics Division director, in a press release. “We’re fortunate we’ve had 15 years – so far – to use Chandra to advance our understanding of stars, galaxies, black holes, dark energy, and the origin of the elements necessary for life.”

The telescope launched into space in 1999 aboard the space shuttle and currently works at an altitude as high as 86,500 miles (139,000 miles). It is named after Indian-American astrophysicist Subrahmanyan Chandrasekhar; the name “Chandra” also means “moon” or “luminous” in Sanskrit.

And there’s more to come. You can learn more about Chandra’s greatest discoveries and its future in this Google+ Hangout, which will start at 3 p.m. EDT (7 p.m. EDT) at this link.

June 26, 2014December 23, 2015 by Shannon Hall

Superluminous Supernova Puzzles Astronomers

Before (left) and after (center) images of the region where DES13S2cmm was discovered. On the right is a subtraction of these two images, showing a bright new object at the center -- a supernova. Credit: Dark Energy Survey

Supernovae are surprisingly dependable. These brilliant and powerful explosions that mark the end of massive stars’ lives tend to shine anywhere from one hundred million to a few billion times brighter than the Sun for weeks on end. And their intrinsic brightness is always well known.

But in recent years a rare class of cosmic explosions, which are tens to hundreds of times more luminous than ordinary supernovae, has been discovered. And now one of these odd superluminous supernovae is mystifying astronomers further, with characteristics that simply don’t add up.

The Dark Energy Survey (DES) came online in August 2013 in order to investigate millions of galaxies for the subtle effects of weak lensing, the phenomenon where intervening invisible matter causes distant galaxies to appear minutely sheared and stretched.

The survey started off with a bang; its first images revealed a rare superluminous supernova, dubbed DES13S2cmm, 7.8 billion light-years away.

“Fewer than forty such supernovae have ever been found and I never expected to find one in the first DES images,” said Andreas Papadopoulos from the University of Portsmouth in a press release. “As they are rare, each new discovery brings the potential for greater understanding — or more surprises.”

The problem is this: DES13S2cmm doesn’t easily match the typical characteristics of a superluminous supernova. The stellar explosion could be seen in the data six months later, much longer than most other superluminous supernovae observed to date.

“Its unusual, slow decline was not apparent at first,” said Mark Sullivan from Southampton University. “But as more data came in and the supernova stopped getting fainter, we would look at the light curve and ask ourselves, ‘what is this?’ ”

So Sullivan decided to investigate further. But understanding its origins are proving difficult.

For some supernovae, the optical light we see is actually created by radioactivity. In fact, supernovae tend to create large amounts of radioactive elements, which don’t occur naturally on Earth. Nickel-56, with a half-life of roughly six days, is a common example.

As the nickel decays into cobalt, it releases gamma rays, which are trapped by the other material ejected by the supernova. These trapped rays heat up the surrounding material until it radiates in the optical. In this case, the peak magnitude of the supernova is directly proportional to the amount of nickel-56 created in the explosion.

“We have tried to explain the supernova as a result of the decay of the radioactive isotope nickel-56,” said coauthor Dr Chris D’Andrea of the University of Portsmouth. “But to match the peak brightness, the explosion would need to produce more than three times the mass of our Sun of the element. And even then the behavior of the light curve doesn’t match up.”

So the team is now investigating other explanations. In one intriguing scenario the supernova was relatively normal but created a magnetar — an extremely dense and highly magnetic neutron star that’s millions of times more powerful than the strongest magnets on Earth — whose energy made the explosion exceptionally bright.

But this explanation doesn’t match the data either.

A few months ago a team of astronomers led by Robert Quimby explained a superluminous supernovae, PS1-10afx, by a chance cosmic alignment, where intervening matter worked like a lens to deflect and intensify the background light for a typical Type Ia supernova. D’Andrea, however, doesn’t believe this is the case here.

“DES13S2cmm looks nothing like a normal type of supernova, either in its photometric evolution or its spectroscopy,” D’Andrea told Universe Today. “So while we can never be sure that a very faint but very massive galaxy lies between us and another object and is serendipitously brightening the object, there is no need to adopt that assumption in the case of DES13S2cmm.”

chance cosmic alignment — where intervening matter worked like a lens to deflect and intensify the background light – See more at: http://www.skyandtelescope.com/astronomy-news/stellar-science/mysteriously-bright-supernova-explained/#sthash.m7Z8PJ3k.dpuf

So astronomers are heading back to the drawing board.

“With so few known, it’s hard to really understand their properties in detail,” said Bob Nichol from the University of Portsmouth. “DES should find enough of these objects to allow us to understand superluminous supernovae as a population. But if some of these discoveries prove as difficult to interpret as DES13S2cmm, we’re prepared for the unusual.”

The results will be presented today at the National Astronomy Meeting 2014 in Portsmouth.

May 22, 2014December 23, 2015 by Bob King

New Supernova Pops in Bright Galaxy M106 in the ‘Hunting Dogs’

The new Type II supernova is nestled up to the nucleus of the galaxy in this photo taken May 21 with a 17-inch telescope. Credit: Gianluca Masi, Francesca Nocentini and Patrick Schmeer

A supergiant star exploded 23.5 million years ago in one of the largest and brightest nearby galaxies. This spring we finally got the news. In April, the Katzman Automatic Imaging Telescope (KAIT) as part of the Lick Observatory Supernova Search, photographed a faint “new star” very close to the bright core of M106, a 9th magnitude galaxy in Canes Venatici the Hunting Dogs.

The core of a red or blue supergiant moments before exploding as a supernova looks like an onion with multiple elements "burning" through the fusion process to create the heat to stay the force of gravity. Fusion stops at iron. With no energy pouring from the central core to keep the other elements cooking, the star collapses and the rebounding shock wave tears it apart. — The inner core of a red or blue supergiant moments before exploding as a supernova looks like an onion with multiple elements “burning” through the fusion process to create the heat and pressure that stays the force of gravity. Fusion stops at iron. With no energy pouring from the central core to keep the other elements cooking, the star collapses and the rebounding shock wave tears it apart.

A study of its light curve indicated a Type II supernova – the signature of a rare supergiant star ending its life in the most violent way imaginable. A typical supergiant star is 8 to 12 times more massive than the sun and burns at a much hotter temperature, rapidly using up its available fuel supply as it cooks lighter elements like hydrogen and helium into heavier elements within its core. Supergiant lifetimes are measured in the millions of years (10-100 million) compared to the frugal sun’s 11 billion years. When silicon fuses to create iron, a supergiant reaches the end of the line – iron can’t be fused or cooked into another heavier element – and its internal “furnace” shuts down. Gravity takes over and the whole works collapses in upon itself at speeds up to 45,000 miles per second.

When the outer layers reached the core, they crushed it into a dense ball of subatomic particles and send a powerful shock wave back towards the surface that rips the star to shreds. A supernova is born! Newly-minted radioactive forms of elements like nickel and cobalt are created by the tremendous pressure and heat of the explosion. Their rapid decay into stable forms releases energy that contributes to the supernova’s light.

This Hubble Space Telescope image shows how spectacular M106 truly is. Its spiral arms are dotted with dark lanes of dust, young star clusters rich with hot, blue stars and tufts of pink nebulosity swaddling newborn stars. The galaxy is the 106th entry in the 18th century French astronomer Charles Messier's famous catalog. Credit: NASA / ESA — This Hubble Space Telescope image shows how spectacular M106 truly is. Dark filaments of dust are silhouetted against billions of unresolved suns. Young star clusters rich with hot, blue stars and tufts of pink nebulosity swaddling newborn stars ornament the galaxy’s spiral arms. A supermassive black hole rumbles at the heart of the galaxy. M106 is the 106th entry in Charles Messier’s famous catalog created in the 18th century. It’s located 23.5 million light years away. Credit: NASA / ESA

For two weeks, the supernova in M106 remained pinned at around magnitude +15, too faint to tease out from the galaxy’s bright, compact nucleus for most amateur telescopes. But a photograph taken by Gianluca Masi and team on May 21 indicate it may have brightened somewhat. They estimated its red magnitude – how bright it appears when photographed through a red filter – at +13.5. A spectrum made of the object reveals the ruby emission of hydrogen light, the telltale signature of a Type II supernova event.

At magnitude +9, M106 visible in almost any telescope and easy to find. Start just above the Bowl of the Big Dipper which stands high in the northwestern sky at nightfall in late May. The 5th magnitude stars 5 CVn (5 Canes Venatici) and 3 CVn lie near the galaxy. Star hop from the Bowl to these stars and then over to M106. Stars plotted to mag. +8. Click to enlarge. Stellarium

Visually the supernova will appear fainter because our eyes are more sensitive to light in the middle of the rainbow spectrum (green-yellow) than the reds and purple that bracket either side. I made a tentative observation of the object last night using a 15-inch (37-cm) telescope and hope to see it more clearly tonight from a darker sky. We’ll keep you updated on our new visitor’s brightness as more observations and photographs come in. You can also check Dave Bishop’s Latest Supernovae site for more information and current images.

Even if the supernova never gets bright enough to see in your telescope, stop by M106 anyway. It’s big, easy to find and shows lots of interesting structure. Spanning 80,000 light years in diameter, M106 would be faintly visible with the naked eye were it as close as the Andromeda Galaxy. In smaller scopes the galaxy’s bright nucleus stands out in a mottled haze of pearly light; 8-inch(20-cm) and larger instrument reveal the two most prominent spiral arms. M106 is often passed up for the nearby more famous Whirlpool Galaxy (M51). Next time, take the detour. You won’t be disappointed.

May 21, 2014December 23, 2015 by Elizabeth Howell

New Supernova Likely Arose From Massive Wolf-Rayet Star

M1-67 is the youngest wind-nebula around a Wolf-Rayet star, called WR124, in our Galaxy. Credit: ESO

They’ve been identified as possible causes for supernovae for a while, but until now, there was a lack of evidence linking massive Wolf-Rayet stars to these star explosions. A new study was able to find a “likely” link between this star type and a supernova called SN 2013cu, however.

“When the supernova exploded, it flash ionized its immediate surroundings, giving the astronomers a direct glimpse of the progenitor star’s chemistry. This opportunity lasts only for a day before the supernovablast wave sweeps the ionization away. So it’s crucial to rapidly respond to a young supernova discovery to get the flash spectrum in the nick of time,” the Carnegie Institution for Science wrote in a statement.

“The observations found evidence of composition and shape that aligns with that of a nitrogen-rich Wolf-Rayet star. What’s more, the progenitor star likely experienced an increased loss of mass shortly before the explosion, which is consistent with model predictions for Wolf-Rayet explosions.”

NGC 3199 - Credit: Ken Crawford — NGC 3199 – Credit: Ken Crawford

The star type is known for lacking hydrogen (in comparison to other stars) — which makes it easy to identify spectrally — and being large (upwards of 20 times more massive than our Sun), hot and breezy, with fierce stellar winds that can reach more than 1,000 kilometres per second. This particular supernova was spotted by the Palomar 48-inch telescope in California, and the “likely progenitor” was found about 15 hours after the explosion.

Researchers also noted that the new technique, called “flash spectroscopy”, allows them to look at stars over a range of about 100 megaparsecs or more than 325 million light years — about five times further than what previous observations with the Hubble Space Telescope revealed.

The research was published in Nature. It was led by Avishay Gal-Yam of the Weizmann Institute of Science in Israel.

Source: Carnegie Institution for Science

April 25, 2014December 23, 2015 by Elizabeth Howell

Gallery: Incredible Mirages In Space Show Dark Matter, Supernovas And Galaxies

This artist’s impression of a supernova shows the layers of gas ejected prior to the final deathly explosion of a massive star. Credit: NASA/Swift/Skyworks Digital/Dana Berry

How can an exploding star appear far brighter than expected? This question vexed astronomers since the discovery of PS1-10afx, supernova that was about 30 times more luminous than other Type 1A supernovas. Astronomers have just confirmed in Science that it was likely due to well-known illusion in space.

The mirage is called a gravitational lens that happens when a huge object in the foreground (like a galaxy) bends the light of an object in the background. Astronomers use this trick all the time to spy on galaxies and even to map dark matter, the mysterious substance believed to make up most of the universe.

Check out some spectacular images below of the phenomenon in action.