MPA: The Brightest Explosion in the Universe

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MPA: The Brightest Explosion in the Universe

Post by bystander » Fri Jan 24, 2020 8:51 pm

Progress in Understanding the Brightest Explosions in the Universe
Max Planck Institute for Astrophysics | 2020 Jan 23
Some unidentified features in one of the brightest stellar explosions ever witnessed, SN 2006gy, have now been explained by researchers at the Max Planck Institute for Astrophysics. The spectral lines arise from neutral iron - very unusual for such a high-energy event - and imply that more than a third of a solar mass of this heavy element was created. The dominance of iron in the spectrum rules out several previously proposed scenarios for SN 2006gy and instead opened up the door for a new one.

Superluminous supernovae are the brightest explosions in the cosmos. Over a few months they radiate as much energy as the Sun does over its entire lifetime, reaching a peak brightness exceeding that of an entire galaxy. The origin of this energy, and what kind of stellar progenitor system has exploded, are still unclear.

One of the most studied such objects is SN 2006gy, which was first observed in 2006. It showed signs of interaction between the supernova explosion and circumstellar material, which had been ejected previously. Many theories have been put forth for SN 2006gy, including collision of shells ejected subsequently by a very massive star, large amounts of radioactivity, or a massive stellar explosion called a core-collapse supernova, which arises when the compact core of a massive star collapses to a neutron star, interacting with its own wind. ...

A type Ia supernova at the heart of superluminous transient SN 2006gy ~ Anders Jerkstrand, Keiichi Maeda, Koji S. Kawabata
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Re: MPA: The Brightest Explosion in the Universe

Post by Ann » Sat Jan 25, 2020 5:26 am


























So hypernova SN 2006gy, located in host galaxy NGC 1260, may have been a "Type Ia supernova on steroids"! :shock:
Anders Jerkstrand wrote:

The researchers propose that the progenitor system was a double star consisting of a white dwarf in a close orbit with a more massive hydrogen-rich companion star. As the hydrogen-rich star expanded its size - such giant stars can become as big as the Earth-Sun distance or even bigger - the white dwarf got trapped in the larger star’s atmosphere and spiralled in towards the center. In this process the envelope is ejected. Once the white dwarf reaches the core of the other star, it explodes. The expanding shock wave of this Ia supernova then collides with the previously ejected envelope, and in this gigantic collision extremely intense light is radiated. By modelling this light, the researchers could demonstrate that the suggested scenario reproduces the key properties of SN 2006gy - in particular including features of neutral iron.
Ejecting outer shell.
So the white dwarf spiralled in toward its companion's center.

On its way into the other star's center, the white dwarf caused the other star's envelope to be ejected.

As soon as the white dwarf reached the other star's center, it exploded. Possibly the explosion itself was extra big, because two stellar cores were involved in the explosion. And then the shock wave hit the massive gaseous envelope that had previously been ejected, causing a titanic cosmic collision that undoubtedly made all the involved electrons radiate crazily all across the electromagnetic spectrum.


Shock wave about to hit envelope.
To me, the suggestion that SN 2006gy was a Type Ia supernova clears up a mystery. The appearance of host galaxy NGC 1260 makes it clear that there is extremely little star formation in this galaxy, if any at all. The suggestion that a galaxy with extremely little star formation should contain a super duper extra supermassive star capable of creating a core-collapse supernova brighter than any supernova that human astronomers have ever witnessed just didn't make sense.

But supernovas Type Ia can happen in all kinds of galaxies, because they don't require very massive stars. So to me, it makes perfect sense that SN 2006gy should be a Type Ia supernova with a twist.


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Re: MPA: The Brightest Explosion in the Universe

Post by neufer » Sat Jan 25, 2020 3:12 pm

https://en.wikipedia.org/wiki/SN_2006gy wrote:


<<SN 2006gy was an extremely energetic supernova, also referred to as a hypernova or quark-nova,that was discovered on September 18, 2006. It was first observed by Robert Quimby and P. Mondol. In May 2007 NASA and several of the astronomers announced the first detailed analyses of the supernova, describing it as the "brightest stellar explosion ever recorded". When a star is very massive, its core can produce so much gamma-ray light that some of the energy from the radiation is converted into particle and anti-particle pairs. The resulting drop in [radiation pressure] causes the star to collapse under its own huge gravity. After this violent collapse, runaway thermonuclear reactions (not shown here) ensue and the star explodes, spewing the remains into space. In October 2007 Quimby announced that SN 2005ap had broken SN 2006gy's record as the brightest-ever recorded supernova, and several subsequent discoveries are brighter still.>>
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Re: MPA: The Brightest Explosion in the Universe

Post by Ann » Sun Jan 26, 2020 4:50 am

neufer wrote:
Sat Jan 25, 2020 3:12 pm
https://en.wikipedia.org/wiki/SN_2006gy wrote:
In October 2007 Quimby announced that SN 2005ap had broken SN 2006gy's record as the brightest-ever recorded supernova, and several subsequent discoveries are brighter still.>>
The brightest recorded supernova so far appears to be ASASSN-15lh, which according to Wikipedia was 20 times brighter at its peak than the combined light emitted by the Milky Way. Now we are talking about a supernova that is brighter than an entire galaxy.

But it may not have been brighter than its host galaxy.
Wikipedia wrote:

The host galaxy for ASASSN-15lh is APMUKS(BJ) B215839.70−615403.9, much larger and more luminous than the Milky Way. The host galaxy has visual magnitude 18.5 and is red in color with a low rate of star formation. It maintained a steady brightness until the supernova lit up. The strongest parts of the galaxy's spectrum have wavelengths around 1 μm in the near infrared.
So here we have another galaxy that is red in color, has a low rate of star formation, and hosts a super duper totally record-breaking whopper of a supernova. I find it very hard to believe that the progenitor of a supernova in a galaxy low in star formation is an especially massive star.

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Re: MPA: The Brightest Explosion in the Universe

Post by neufer » Sun Jan 26, 2020 2:04 pm

Ann wrote:
Sun Jan 26, 2020 4:50 am

The brightest recorded supernova so far appears to be ASASSN-15lh, which according to Wikipedia was 20 times brighter at its peak than the combined light emitted by the Milky Way. Now we are talking about a supernova that is brighter than an entire galaxy.

But it may not have been brighter than its host galaxy.
Wikipedia wrote:

The host galaxy for ASASSN-15lh is APMUKS(BJ) B215839.70−615403.9, much larger and more luminous than the Milky Way. The host galaxy has visual magnitude 18.5 and is red in color with a low rate of star formation. It maintained a steady brightness until the supernova lit up. The strongest parts of the galaxy's spectrum have wavelengths around 1 μm in the near infrared.
APMUKS(BJ) B215839.70−615403.9 in the constellation Indus reached a peak apparent magnitude of 16.9 or 1.6 magnitudes (4.3 times) brighter than the host galaxy's visual magnitude of 18.5.
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Re: MPA: The Brightest Explosion in the Universe

Post by neufer » Wed Jan 29, 2020 5:53 pm

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Re: MPA: The Brightest Explosion in the Universe

Post by saturno2 » Wed Jan 29, 2020 10:21 pm

neufer wrote:
Sat Jan 25, 2020 3:12 pm
https://en.wikipedia.org/wiki/SN_2006gy wrote:


<<SN 2006gy was an extremely energetic supernova, also referred to as a hypernova or quark-nova,that was discovered on September 18, 2006. It was first observed by Robert Quimby and P. Mondol. In May 2007 NASA and several of the astronomers announced the first detailed analyses of the supernova, describing it as the "brightest stellar explosion ever recorded". When a star is very massive, its core can produce so much gamma-ray light that some of the energy from the radiation is converted into particle and anti-particle pairs. The resulting drop in [radiation pressure] causes the star to collapse under its own huge gravity. After this violent collapse, runaway thermonuclear reactions (not shown here) ensue and the star explodes, spewing the remains into space. In October 2007 Quimby announced that SN 2005ap had broken SN

2006gy's record as the brightest-ever recorded supernova, and several subsequent discoveries are brighter still.
>>
Why SN2006gy is " quark-nova "

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Re: MPA: The Brightest Explosion in the Universe

Post by neufer » Thu Jan 30, 2020 3:52 am

saturno2 wrote:
Wed Jan 29, 2020 10:21 pm

Why SN2006gy is " quark-nova "
What I described above is NOT a "quark-nova."

A "quark-nova" is yet another hypothetical explanation for extra bright supernovae like SN 2006gy.
https://en.wikipedia.org/wiki/Quark-nova wrote:
<<A quark-nova is the hypothetical violent explosion resulting from the conversion of a neutron star to a quark star. Analogous to a supernova heralding the birth of a neutron star, a quark nova signals the creation of a quark star. The term quark-novae was coined in 2002 by Dr. Rachid Ouyed (currently at the University of Calgary, Canada) and Drs. J. Dey and M. Dey (Calcutta University, India).

When a neutron star spins down, it may convert to a quark star through a process known as quark deconfinement. The resultant star would have quark matter in its interior. The process would release immense amounts of energy, perhaps explaining the most energetic explosions in the universe; calculations have estimated that as much as 1047 J could be released from the phase transition inside a neutron star. Quark-novae may be one cause of gamma ray bursts. According to Jaikumar et al., they may also be involved in producing heavy elements such as platinum through r-process nucleosynthesis.

Rapidly spinning neutron stars with masses between 1.5 and 1.8 solar masses are theoretically the best candidates for conversion due to spin down of the star within a Hubble time. This amounts to a small fraction of the projected neutron star population. A conservative estimate based on this, indicates that up to two quark-novae may occur in the observable universe each day.

Theoretically, quark stars would be radio-quiet, so radio-quiet neutron stars may be quark stars. Direct evidence for quark-novae is scant; however, recent observations of supernovae SN 2006gy, SN 2005gj and SN 2005ap may point to their existence.>>
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Re: MPA: The Brightest Explosion in the Universe

Post by Ann » Fri Jan 31, 2020 3:30 pm

neufer wrote:
Thu Jan 30, 2020 3:52 am
https://en.wikipedia.org/wiki/Quark-nova wrote:
<<A quark-nova is the hypothetical violent explosion resulting from the conversion of a neutron star to a quark star. Analogous to a supernova heralding the birth of a neutron star, a quark nova signals the creation of a quark star. The term quark-novae was coined in 2002 by Dr. Rachid Ouyed (currently at the University of Calgary, Canada) and Drs. J. Dey and M. Dey (Calcutta University, India).

When a neutron star spins down, it may convert to a quark star through a process known as quark deconfinement. The resultant star would have quark matter in its interior. The process would release immense amounts of energy, perhaps explaining the most energetic explosions in the universe; calculations have estimated that as much as 1047 J could be released from the phase transition inside a neutron star.
1047 J doesn't sound like all that much. Maybe you mean 1047J ?

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Re: MPA: The Brightest Explosion in the Universe

Post by neufer » Fri Jan 31, 2020 4:35 pm

Ann wrote:
Fri Jan 31, 2020 3:30 pm
neufer wrote:
Thu Jan 30, 2020 3:52 am
https://en.wikipedia.org/wiki/Quark-nova wrote:
<<A quark-nova is the hypothetical violent explosion resulting from the conversion of a neutron star to a quark star. Analogous to a supernova heralding the birth of a neutron star, a quark nova signals the creation of a quark star. When a neutron star spins down, it may convert to a quark star through a process known as quark deconfinement. The resultant star would have quark matter in its interior. The process would release immense amounts of energy, perhaps explaining the most energetic explosions in the universe; calculations have estimated that as much as 1047 J could be released from the phase transition inside a neutron star.
1047 J doesn't sound like all that much. Maybe you mean 1047J ?
  • – Three quarks for Mistress Mark!
    Sure she hasn't got much of a bark
    And sure any she has it's all beside the mark.
https://www.etymonline.com/search?q=bark wrote:
bark (n) "any small vessel or ship," early 15c., from Middle French barque "boat" (15c.), from Late Latin barca, which is probably cognate with Vulgar Latin *barica (see barge (n.)).
https://en.wikipedia.org/wiki/Design_1047_battlecruiser wrote: <<Design 1047 was a series of plans for a class of Dutch battlecruisers prior to the Second World War. The ships were intended to counter a perceived threat posed by Imperial Japanese aggression to the Dutch colonies in the East Indies. Dutch intelligence believed that the Imperial Japanese Navy would deploy its aircraft carriers and battleships against their counterparts of the United States Navy and the British Royal Navy, leaving heavy and light cruisers, along with seaplane carriers, as the largest ships available for an advance into the East Indies. As such, the 1047s were shaped by the need to be able to fight their way through a fleet composed of these ships and smaller destroyers. It was hoped that this capability would allow the battlecruisers to act as a fleet in being. The first 1047-class ship was scheduled to be completed in 1944, so would have been too late to stop the Japanese advance into the Dutch East Indies. Due to the war, final plans for the ships were never completed, and the ships were never constructed.>>
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