Mar 15

An explosive quartet

Source: ESA/Hubble

heic1505aGalaxy cluster MACS j1149.5+223 and a supernova four times over.
Image credits:NASA, ESA, S. Rodney (John Hopkins University, USA) and the FrontierSN team; T. Treu (University of California Los Angeles, USA), P. Kelly (University of California Berkeley, USA) and the GLASS team; J. Lotz (STScI) and the Frontier Fields team; M. Postman (STScI) and the CLASH team; and Z. Levay (STScI)


Astronomers using the NASA/ESA Hubble Space Telescope have, for the first time, spotted four images of a distant exploding star. The images are arranged in a cross-shaped pattern by the powerful gravity of a foreground galaxy embedded in a massive cluster of galaxies. The supernova discovery paper will appear on 6 March 2015 in a special issue of Science celebrating the centenary of Albert Einstein’s theory of general relativity.(learn more)

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Aug 12

A Blue Whirlpool in The River — Tranquil galaxy home to violent events

Source: ESO Photo Release eso1231

VLT image of the spiral galaxy NGC 1187.
Image credit: ESO

A new image taken with ESO’s Very Large Telescope shows the galaxy NGC 1187. This impressive spiral lies about 60 million light-years away in the constellation of Eridanus (The River). NGC 1187 has hosted two supernova explosions during the last thirty years, the latest one in 2007. This picture of the galaxy is the most detailed ever taken.(read more)

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Jun 12

Why Won't the Supernova Explode?

Source: NASA Science Casts

A question has been troubling astronomers: Why won't the supernova explode? While real stars blow up, computer models of massive dying stars do not result in much of a bang. NASA has launched a new observatory named "NuSTAR" to seek out the missing physics of stellar explosions.

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Jan 12

Hubble solves mystery on source of supernova in nearby galaxy

Source: NASA Hubble Release 12-012

Emergence of an exploding star, called a supernova in Hubble Deep Field.
Image credits: NASA, ESA, A. Riess (Space Telescope Science Institute and The
Johns Hopkins University), and S. Rodney (The Johns Hopkins University)

Using NASA's Hubble Space Telescope, astronomers have solved a longstanding mystery on the type of star, or so-called
progenitor, which caused a supernova seen in a nearby galaxy. The finding yields new observational data for pinpointing one of several scenarios that trigger such outbursts.

Based on previous observations from ground-based telescopes, astronomers knew the supernova class, called a Type Ia, created a remnant named SNR 0509-67.5, which lies 170,000 light-years away in the Large Magellanic Cloud galaxy.

Theoretically, this kind of supernova explosion is caused by a star spilling material onto a white dwarf companion, the compact remnant of a normal star, until it sets off one of the most powerful explosions in the universe.

Astronomers failed to find any remnant of the companion star, however, and concluded that the common scenario did not apply in this case, although it is still a viable theory for other Type Ia supernovae. (read more)

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Aug 11

New supernova found in M101

Source: Palomar Transient Factory

Detection of Supernova PTF11klyin M101 (colour inverted(see original)).
Original image credit: Palomar Transient Factory.

On August 24th, new supernova was found in M101 by Palomar Transient Factory, a fully-automated, wide-field survey aimed at a systematic exploration of the optical transient sky. This supernova, categorized as PTF11kly, is located 58″.6 west and 270″.7 south of the center of M101.(learn more)

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Jul 11

Herschel helps solve mystery of cosmic dust origins

Source: NASA/JPL

Supernova remnant called SN 1987A.
Image credit: ESA/NASA-JPL/UCL/STScI

New observations from the infrared Herschel Space Observatory reveal that an exploding star expelled the equivalent of between 160,000 and 230,000 Earth masses of fresh dust. This enormous quantity suggests that exploding stars, called supernovae, are the answer to the long-standing puzzle of what supplied our early universe with dust.(read more)

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Jul 11

‘Zombie' Stars Key to Measuring Dark Energy

Source: UCSB Press Release

Chandra X-ray image of Tycho's supernova remnant.
Image credit: NASA/Chandra X-ray Observatory.

"Zombie" stars that explode like bombs as they die, only to revive by sucking matter out of other stars. According to an astrophysicist at UC Santa Barbara, this isn't the plot for the latest 3D blockbuster movie. Instead, it's something that happens every day in the universe –– something that can be used to measure dark energy.

This special category of stars, known as Type Ia supernovae, help to probe the mystery of dark energy, which scientists believe is related to the expansion of the universe. (read more)

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May 11

Carina Nebula: Nearby supernova factory ramps up

Source: NASA/Chandra

Image credit: NASA/CXC/PSU/L.Townsley et al.

A new Chandra image shows the Carina Nebula, a star-forming region in the Sagittarius-Carina arm of the Milky Way a mere 7,500 light years from Earth. Chandra's sharp X-ray vision has detected over 14,000 stars in this region, revealed a diffuse X-ray glow, and provided strong evidence that massive stars have already self-destructed in this nearby supernova factory.(read more)

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May 11

Tycho's Supernova Remnant: NASA'S Chandra Finds New Evidence on Origin of Supernovas

Source: Chandra X-ray Observatory

Image credits: NASA/CXC/Chinese Academy of Sciences/F. Lu et al

This new image of Tycho's supernova remnant, dubbed Tycho for short, contains striking new evidence for what triggered the original supernova explosion, as seen from Earth in 1572. Tycho was formed by a Type Ia supernova, a category of stellar explosion used in measuring astronomical distances because of their reliable brightness. (read more)

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Mar 11

Tycho's Supernova Remnant: Exploding Stars and Stripes

Source: Chandra

Very deep Chandra observation of the Tycho supernova remnant.
Image credit: NASA/CXC/Rutgers/K.Eriksen et al.

A long Chandra observation of Tycho has revealed a pattern of X-ray "stripes" never seen before in a supernova remnant.

This result could explain how some of the extremely energetic particles bombarding the Earth, called cosmic rays, are produced.(read  source)

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Jan 11

Crab Nebula Supernova reveals its secrets

Source: SLAC Presse Release

The Crabe Nebula.
Image credits: NASA/ESA

The Crab Nebula, one of our best-known and most stable neighbors in the winter sky, is shocking scientists with its propensity for fireworks—gamma-ray flares set off by the most energetic particles ever traced to a specific astronomical object. The discovery, reported today by scientists working with two orbiting telescopes, is leading researchers to rethink their ideas of how cosmic particles are accelerated.

"We were dumbfounded," said Roger Blandford, who directs the Kavli Institute for Particle Astrophysics and Cosmology, jointly located at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University. "It's an emblematic object," he said. The Crab Nebula, also known as M1, was the first astronomical object catalogued in 1771 by Charles Messier. "It's a big deal historically," Blandford continued, "and we're making an amazing discovery about it."

Blandford was part of a KIPAC team led by scientists Rolf Buehler and Stefan Funk that used observations from the Large Area Telescope, one of two primary instruments aboard NASA's Fermi Gamma-ray Space Telescope, to confirm one flare and discover another. Their report was posted online today in Science Express alongside a report from the Italian orbiting telescope Astro-rivelatore Gamma a Immagini LEggero, or AGILE, which also detected gamma-ray flares in the Crab Nebula.

The Crab Nebula, and the rapidly spinning neutron star that powers it, are the remnants of a supernova explosion documented by Chinese and Middle Eastern astronomers in 1054. After shedding much of its outer gases and dust, the dying star collapsed into a pulsar, a super-dense, rapidly spinning ball of neutrons. The Crab Nebula's pulsar emits a pulse of radiation every 33 milliseconds, like clockwork.

Though it's only 10 miles across, the amount of energy the pulsar releases is enormous, lighting up the Crab Nebula until it shines 75,000 times more brightly than the sun. Most of this energy is contained in a particle wind of energetic electrons and positrons traveling close to the speed of light. These electrons and positrons interact with magnetic fields and low-energy photons to produce the famous glowing tendrils of dust and gas Messier mistook for a comet over 200 years ago.

The particles are even forceful enough to produce the gamma rays the LAT normally observes during its regular surveys of the sky. But those particles did not cause the dramatic flares.

Each of the two flares the LAT observed lasted a few days before the Crab Nebula's gamma-ray output returned to more normal levels. According to Funk, the short duration of the flares points to synchrotron radiation, or radiation emitted by electrons accelerating in the magnetic field of the nebula, as the cause. And not just any accelerated electrons: the flares were caused by super-charged electrons of up to 1015 electron volts, or 10 quadrillion electron volts, approximately 1,000 times more energetic than the protons accelerated by the Large Hadron Collider in Europe, the world's most powerful man-made particle accelerator, and more than 15 orders of magnitude greater than photons of visible light.

"The strength of the gamma-ray flares shows us they were emitted by the highest-energy particles we can associate with any discrete astrophysical object," Funk said.

Not only are the electrons surprisingly energetic, added Buehler, but, "the fact that the intensity is varying so rapidly means the acceleration has to happen extremely fast." This challenges current theories about the way cosmic particles are accelerated. These theories cannot easily account for the extreme energies of the electrons or the speed with which they're accelerated.

The discovery of the Crab Nebula's gamma-ray flares raises one obvious question: how can the nebula do that? Obvious question, but no obvious answers. The KIPAC scientists all agree they need a closer look at higher resolutions and in a variety of wavelengths before they can make any definitive statements. The next time the Crab Nebula flares, the Fermi LAT team will not be the only team gathering data. They'll need all the help they can get to decipher the mysteries of the Crab Nebula

"We thought we knew the essential ingredients of the Crab Nebula," Funk said, "but that's no longer true. It's still surprising us."

The Fermi Gamma-ray Space Telescope was constructed through an astrophysics and particle physics partnership developed by NASA in collaboration with the U.S. Department of Energy Office of Science, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the United States. SLAC National Accelerator Laboratory managed construction of the LAT and now plays the central role in science operations, data processing and making scientific data available to collaborators for analysis.

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Dec 10

Beautiful Supernova Bubble

Source: NASA/Chandra (Image Release)

SNR 0509-67.5
Credits: X-ray: NASA/CXC/SAO/J.Hughes et al.
Optical: NASA/ESA/Hubble Heritage Team (STScI/AURA)

This colorful creation was made by combining data from two of NASA's Great Observatories. Optical data of SNR 0509-67.5 and its accompanying star field, taken with the Hubble Space Telescope, are composited with X-ray energies from the Chandra X-ray Observatory. The result shows soft green and blue hues of heated material from the X-ray data surrounded by the glowing pink optical shell which shows the ambient gas being shocked by the expanding blast wave from the supernova. Ripples in the shell's appearance coincide with brighter areas of the X-ray data.

The Type 1a supernova that resulted in the creation of SNR 0509-67.5 occurred nearly 400 years ago for Earth viewers. The supernova remnant, and its progenitor star reside in the Large Magellanic Cloud (LMC), a small galaxy about 160,000 light-years from Earth. The bubble-shaped shroud of gas is 23 light-years across and is expanding at more than 11 million miles per hour (5,000 kilometers per second).

Data from Hubble's Advanced Camera for Surveys, taken in 2006 with a filter that isolates light from glowing hydrogen were combined with visible-light images of the surrounding star field that were imaged with Hubble's Wide Field Camera 3 in 2010. These data were then merged with X-ray data from the Chandra X-ray Observatory taken with the Advanced CCD Imaging Spectrometer (ACIS) in 2000 and 2007.

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Dec 10

Hubble spots a celestial bauble

Source: ESA/Hubble

Hubble's image of SNR B0509-67.5.
Image credit:NASA, ESA, and the Hubble Heritage Team (STScI/AURA).
Acknowledgement: J. Hughes (Rutgers University)

Hubble has spotted a festive bauble of gas in our neighbouring galaxy, the Large Magellanic Cloud. Formed in the aftermath of a supernova explosion that took place four centuries ago, this sphere of gas has been snapped in a series of observations made between 2006 and 2010.

The delicate shell, photographed by the NASA/ESA Hubble Space Telescope, appears to float serenely in the depths of space, but this apparent calm hides an inner turmoil. The gaseous envelope formed as the expanding blast wave and ejected material from a supernova tore through the nearby interstellar medium. Called SNR B0509-67.5 (or SNR 0509 for short), the bubble is the visible remnant of a powerful stellar explosion in the Large Magellanic Cloud (LMC), a small galaxy about 160 000 light-years from Earth.

Ripples seen in the shell’s surface may be caused either by subtle variations in the density of the ambient interstellar gas, or possibly be driven from the interior by fragments from the initial explosion. The bubble-shaped shroud of gas is 23 light-years across and is expanding at more than 18 million km/h.

Astronomers have concluded that the explosion was an example of an especially energetic and bright variety of supernova. Known as Type Ia, such supernova events are thought to result when a white dwarf star in a binary system robs its partner of material, taking on more mass than it is able to handle, so that it eventually explodes.(read more)

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Dec 10

WISE Sees an Explosion of Infrared Light

Source: NASA/JPL

Supernova remnant IC 443 as seen by WISE.
Image credit: NASA/JPL-Caltech/UCLA

A circular rainbow appears like a halo around an exploded star in this new view of the IC 443 nebula from NASA's Wide-field Infrared Survey Explorer, or WISE.

When massive stars die, they explode in tremendous blasts, called supernovae, which send out shock waves. The shock waves sweep up and heat surrounding gas and dust, creating supernova remnants like the one pictured here. The supernova in IC 443 happened somewhere between 5,000 and 10,000 years ago.

In this WISE image, infrared light has been color-coded to reveal what our eyes cannot see. The colors differ primarily because materials surrounding the supernova remnant vary in density. When the shock waves hit these materials, different gases were triggered to release a mix of infrared wavelengths.

The supernova remnant's northeastern shell, seen here as the violet-colored semi-circle at top left, is composed of sheet-like filaments that are emitting light from iron, neon, silicon and oxygen gas atoms and dust particles heated by a fast shock wave traveling at about 100 kilometers per second, or 223,700 mph.

The smaller southern shell, seen in bright bluish colors, is constructed of clumps and knots primarily emitting light from hydrogen gas and dust heated by a slower shock wave traveling at about 30 kilometers per second, or 67,100 miles per hour. In the case of the southern shell, the shock wave is interacting with a nearby dense cloud. This cloud can be seen in the image as the greenish dust cutting across IC 443 from the northwest to southeast.

IC 443 can be found near the star Eta Geminorum, which lies near Castor, one of the twins in the constellation Gemini.

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Jan 10

Astronomers Find Rare Beast by New Means

Source: NRAO

Core-collapse supernova explosion
expelling nearly-spherical debris shell.

For the first time, astronomers have found a supernova explosion with properties similiar to a gamma-ray burst, but without seeing any gamma rays from it. The discovery, using the National Science Foundation's Very Large Array (VLA) radio telescope, promises, the scientists say, to point the way toward locating many more examples of these mysterious explosions.

"We think that radio observations will soon be a more powerful tool for finding this kind of supernova in the nearby Universe than gamma-ray satellites," said Alicia Soderberg, of the Harvard-Smithsonian Center for Astrophysics.

The telltale clue came when the radio observations showed material expelled from the supernova explosion, dubbed SN2009bb, at speeds approaching that of light. This characterized the supernova, first seen last March, as the type thought to produce one kind of gamma-ray burst. (read more)

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Jan 10

Violent explosions in space

Credit: Max-Planck-Institute für Astrophysik

Astronomers at the Max-Planck-Institute for Astrophysics in Garching have used computer simulations to confirm that some supernovae are due to the merger of two white dwarfs. White dwarfs are compact remnants of extinguished solar-type stars. As supernovae are used by astronomers to measure cosmic distances and study the expansion history of our Universe, understanding their mechanism is one of the key challenges in astrophysics. This article was published on Nature, 7. January 2010. (read more)

Original publication:
Rüdiger Pakmor, Markus Kromer, Friedrich K. Röpke, Stuart A.Sim, Ashley J. Ruiter, Wolfgang Hillebrandt, "Sub-luminous type Ia supernovae from the mergers of equal-mass white dwarfs with M~0.9 M_solar", Nature, 7. January 2010 (view online, requires subscription)


Website of the linkPfeil.gifsupernova research group
Computer simulation of two merging white dwarfs ( linkPfeil.gifMPEG4 Format , linkPfeil.gifMPEG1 Format )

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Jan 10

Why Won't the Supernova Explode in Computer Models?

Source:NASA Science News

A supercomputer model of a rapidly-spinning, core-collapse supernova.
Credit: Fiona Harrison/Caltech.

A massive old star is about to die a spectacular death. As its nuclear fuel runs out, it begins to collapse under its own tremendous weight. The crushing pressure inside the star skyrockets, triggering new nuclear reactions, setting the stage for a terrifying blast. And then... nothing happens.

At least that's what supercomputers have been telling astrophysicists for decades. Many of the best computer models of supernova explosions fail to produce an explosion. Instead, according to the simulations, gravity wins the day and the star simply collapses. (read more)

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Jan 10

Is Earth threatened by a nearby supernova?

Source: SPACE.com

Kepler's Supernova. Credit: NASA/ESA/JHU/R.Sankrit & W.Blair

The star T Pyxidis, which lies over 3,000 light-years away from the Earth in the constellation Pyxis, was previously thought to be far enough away that if anything happened in the way of a supernova, we'd be pretty safe. According to Edward Sion, Professor of Astronomy and Physics at Villanova University, T Pyxidis may be in fact a "ticking time bomb," and potential threat to the Earth if it were to go supernova, which it may do sometime in the future, though very, very far in the future on our timescale: by Scion's calculations, at least 10 million years.(read more)

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Dec 09

Superbright Supernova explained

Source: Berkeley Lab

Astronomers from the University of California Berkeley have analyzed the explosion, which was recorded by a robotic survey in 2007, and found that it is likely the first confirmed observation ever made of a pair-instability supernova, a type of extremely energetic supernova that has been theorized but never directly confirmed.(Read more)

sn2007bi.discoveryImage source: Weizmann Institute of Science

Related Links: Universe Today

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