Violent Collision with Superluminous Supernovae

In a unique study, an international team of researchers including members from the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) simulated the violent collisions between supernovae and its surrounding gas – which is ejected before a supernova explosion, thereby giving off an extreme brightness.


Many supernovae have been discovered in the last decade with peak luminosity one-to-two orders of magnitude higher than for normal supernovae of known types. These stellar explosions are called Superluminous Supernovae (SLSNe).

Some of them have hydrogen in their spectra, while some others demonstrate a lack of hydrogen. The latter are called Type I, or hydrogen-poor, SLSNe-I. SLSNe-I challenge the theory of stellar evolution, since even normal supernovae are not yet completely understood from first principles.

Led by Sternberg Astronomical Institute researcher Elena Sorokina, who was a guest investigator at Kavli IPMU, and Kavli IPMU Principal Investigator Ken’ichi Nomoto, Scientific Associate Sergei Blinnikov, as well as Project Researcher Alexey Tolstov, the team developed a model that can explain a wide range of observed light curves of SLSNe-I in a scenario which requires much less energy than other proposed models.

The models demonstrating the events with the minimum energy budget involve multiple ejections of mass in presupernova stars. Mass loss and buildup of envelopes around massive stars are generic features of stellar evolution. Normally, those envelopes are rather diluted, and they do not change significantly the light produced in the majority of supernovae.

In some cases, large amount of mass are expelled just a few years before the final explosion. Then, the “clouds” around supernovae may be quite dense. The shockwaves produced in collisions of supernova ejecta and those dense shells may provide the required power of light to make the supernova much brighter than a “naked” supernova without pre-ejected surrounding material.

This class of the models is referred to as “interacting” supernovae. The authors show that the interacting scenario is able to explain both fast and slowly fading SLSNe-I, so the large range of these intriguingly bright objects can in reality be almost ordinary supernovae placed into extraordinary surroundings.

Another extraordinarity is the chemical composition expected for the circumstellar “clouds.” Normally, stellar wind consists of mostly hydrogen, because all thermonuclear reactions happen in the center of a star, while outer layers are hydrogenous.

In the case of SLSNe-I, the situation must be different. The progenitor star must lose its hydrogen and a large part of helium well before the explosion, so that a few months to a few years before the explosion, it ejects mostly carbon and oxygen, and then explode inside that dense CO cloud. Only this composition can explain the spectral and photometric features of observed hydrogen-poor SLSNe in the interacting scenario.

It is a challenge for the stellar evolution theory to explain the origin of such hydrogen- and helium-poor progenitors and the very intensive mass loss of CO material just before the final explosion of the star. These results have been published in a paper accepted by The Astrophysical Journal.

PART-II Nearby Supernovae Found to have Affected Life on Earth

The surface of the Earth was immersed in life-damaging radiation from nearby supernovae on several different occasions over the past nine million years. That is the claim of an international team of astronomers, which has created a computer model that suggests that high-energy particles from the supernovae created ionizing radiation in Earth’s atmosphere that reached ground level. This influx of radiation, the astronomers say, potentially changed the course of the Earth’s climate and the evolution of life.


Earlier this year, two independent teams of astronomers published evidence that several supernovae had exploded some 330 light-years from Earth. Each event showered the solar system in iron-60, an overabundance of which has been found in core samples from the bottom of the Atlantic, Pacific and Indian oceans. A discovery of the same element ‘iron-60’ was found on the moon.

Iron-60 is not all that supernovae produce – they also produce cosmic rays, which are composed of high-energy electrons and atomic nuclei. Previous work by Neil Gehrels of NASA’s Goddard Space Flight Center, was found to be incorrect as he indicated that a supernova would have to explode within 25 light-years of Earth to give our planet a radiation dose strong enough to cause a major mass extinction.


Now, a team led by Brian Thomas of Washburn University, and Adrian Melott of the University of Kansas argues that this conclusion is incorrect. The researchers looked at what would happen if a supernova exploded at a distance of 325 light-years and worked-out how its radiation would affect Earth. They found that cosmic rays accelerated towards Earth by the supernova are a different story. These have energies in the teraelectronvolt (TeV) region and are able to “pass right through the solar wind and Earth’s magnetic field and propagate much further into the atmosphere than cosmic rays normally do.”, says Melott.

When a cosmic ray strikes an air molecule, it produces a shower of secondary particles that is filled with the likes of protons, neutrons and a strong flux of muons. Ordinarily this takes place in the upper atmosphere and can be responsible for ionizing and destroying ozone in the stratosphere. However, the supernova cosmic rays are so energetic that they will pass straight through the stratosphere, lower atmosphere, and down to the surface and deep into the oceans and mantle.


Today, muons contribute a sixth of our annual radiation dose, however, the team calculated a supernova hit would result in a 20-fold increase in the muon flux that would triple the annual radiation dose of life forms on the planet.


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BREAKING NEWS: New Study Shakes Up Science Community Over Historic Cosmic Ray Blast

This news release goes to the heart of my research. It is as if the astrophysics science community comes clean, having hinted of the seriousness charged particles can do to our solar system and of course Earth. What I have been writing about over the last five years regarding possible scenarios based on factual historic data, pertaining to galactic cosmic rays, setting aside the short-term consequences of the Sun’s 22 year cycle apropos to the expansion and contraction of solar rays such as coronal mass ejections, solar flares, coronal holes and filaments.


In short, (encourage you to read last 5 or 6 Science of Cycles newsletters) it is galactic cosmic rays which will usher in the upcoming magnetic reversal. It is these smaller, if not smallest charged particles as measured using a electromagnetic spectrometer which cause the most harmful effects to Earth’s core and humans.

I am placing original excerpts below so you can read the words used as to their emphasis in realizing events such as supernovae’s from our galaxy Milky Way, or perhaps even greater distances from neighboring galaxies or celestial orbs can have a profound effect to our solar system and planet.

_new_equation 2012

Research recently published provided empirical evidence of two prehistoric supernovae exploding about 300 light years from Earth. Now, a follow-up investigation based on computer modeling shows those supernovae likely propagated a significant biological shift on our planet to a long-lasting gust of cosmic radiation, which also affected the atmosphere.

“I was surprised to see as much effect as there was,” said Adrian Melott, professor of physics at the University of Kansas, who co-authored the new paper appearing in The Astrophysical Journal Letters, a peer-reviewed express scientific journal that allows astrophysicists to rapidly publish short notices of significant original research. “I was expecting there to be very little effect at all,” he said. “The supernovae were pretty far away – more than 300 light years – that’s really not very close.”


According to Melott, “The big thing turns out to be the cosmic rays. The really high-energy ones are pretty rare. The high-energy cosmic rays are the ones that can penetrate the atmosphere. They tear up molecules, they can rip electrons off atoms, and that goes on right down to the ground level. Normally that happens only at high altitude.

Melott’s collaborators on the research are Brian Thomas and Emily Engler of Washburn University, Michael Kachelrieß of the Institutt for fysikk in Norway, Andrew Overholt of MidAmerica Nazarene University and Dimitry Semikoz of the Observatoire de Paris and Moscow Engineering Physics Institute.


The boosted exposure to cosmic rays from supernovae could have had “substantial effects on the terrestrial atmosphere and fauna.” Fauna pretty much means ‘all living things’. For instance, the research suggested the supernovae might have caused a 20-fold increase in irradiation by muons at ground level on Earth.

“A muon is a cousin of the electron, a couple of hundred times heavier than the electron – they penetrate hundreds of meters of rock,” Melott said. “Normally there are lots of them hitting us on the ground. They mostly just go through us, but because of their large numbers contribute about 1/6 of our normal radiation dose. So if there were 20 times as many, you’re in the ballpark of tripling the radiation dose.”


Melott said the uptick in radiation from muons would have been high enough to boost the mutation rate and frequency of cancer, but not enormously. Still, if you increased the mutation rate you might speed up evolution.

Indeed, a minor mass extinction around 2.59 million years ago may be connected in part to boosted cosmic rays that could have helped to cool Earth’s climate. The new research results show that the cosmic rays ionize the Earth’s atmosphere in the troposphere – the lowest level of the atmosphere – to a level eight times higher than normal. This would have caused an increase in cloud-to-ground lightning.


Cosmic rays are inescapable throughout the universe. They can rip right through our atmosphere, damaging DNA and possibly causing cancer and memory loss over the long-term.

“There was climate change around this time,” Melott said. Africa dried out, and a lot of the forest turned into savannah. Around this time and afterwards, we started having glaciations – ice ages – over and over again, and it’s not clear why that started to happen. It’s controversial, but maybe cosmic rays had something to do with it.



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