Heavier Stars Might not Explode as Supernovae, Just Quietly Implode Into Black Holes

A supernova is a brilliant end to a giant star. For a brief moment of cosmic time, a star makes one last effort to keep shining, only to fade and collapse on itself. The end result is either a neutron star or a stellar-mass black hole. We’ve generally thought that all stars above about ten solar masses will end as a supernova, but a new study suggests that isn’t the case.

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Astronomers Locate the Source of High-Energy Cosmic Rays

Roughly a century ago, scientists began to realize that some of the radiation we detect in Earth’s atmosphere is not local in origin. This eventually gave rise to the discovery of cosmic rays, high-energy protons and atomic nuclei that have been stripped of their electrons and accelerated to relativistic speeds (close to the speed of light). However, there are still several mysteries surrounding this strange (and potentially lethal) phenomenon.

This includes questions about their origins and how the main component of cosmic rays (protons) are accelerated to such high velocity. Thanks to new research led by the University of Nagoya, scientists have quantified the amount of cosmic rays produced in a supernova remnant for the first time. This research has helped resolve a 100-year mystery and is a major step towards determining precisely where cosmic rays come from.

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It Turns out There Were Supernovae Exploding all Over, we Just Couldn’t see Them

When the poet Horace said “We are but dust and shadow”, he probably didn’t think that dust itself could create a shadow. But it can, and that shadow can obscure even some of the most powerful explosions in the universe.  At least that’s the finding from new research from an international team using data from the recently retired Spitzer telescope.  It turns out dust in far away galaxies can obscure supernovas.

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From the way These Stars Look, a Supernova is Inevitable

Sometimes loud explosions are easier to deal with when you know they’re coming.  They are also easier to watch out for.  So when astronomers from the University of Warwick found a rare tear-drop shaped star, known as HD265435, they knew they were looking at a potential new supernova waiting to happen.  The only caveat – it might not actually happen until 70 million years from now.

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Astronomers saw the Same Supernova Three Times Thanks to Gravitational Lensing. And in Twenty Years They Think They’ll see it one More Time

It is hard for humans to wrap their heads around the fact that there are galaxies so far away that the light coming from them can be warped in a way that they actually experience a type of time delay.  But that is exactly what is happening with extreme forms of gravitational lensing, such as those that give us the beautiful images of Einstein rings.  In fact, the time dilation around some of these galaxies can be so extreme that the light from a single event, such as a supernova, can actually show up on Earth at dramatically different times.  That is exactly what a team led by Dr. Steven Rodney at the University of South Carolina and Dr. Gabriel Brammer of the University of Copenhagen has found. Except three copies of this supernova have already appeared – and the team thinks it will show up again one more time, 20 years from now.

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White Dwarf Measured Before it Exploded as a Supernova

Type Ia supernovae are an important tool for modern astronomy. They are thought to occur when a white dwarf star captures mass beyond the Chandrasekhar limit, triggering a cataclysmic explosion. Because that limit is the same for all white dwarfs, Type Ia supernovae all have about the same maximum brightness. Thus, they can be used as standard candles to determine galactic distances. Observations of Type Ia supernova led to the discovery of dark energy and that cosmic expansion is accelerating.

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Supernova Observed by Astronomers in 1181 Could Have Been a Rare Type 1ax That Leaves Behind a “Zombie Star” Remnant

In 1181 CE, Chinese and Japanese astronomers noticed a “guest star” as bright as Saturn briefly appearing in their night sky. In the thousand years since, astronomers have not been able to pinpoint the origins of that event. New observations have revealed that the “guest star” was a supernova, and a strange one at that. It was a supernova that did not destroy the star, but left behind a zombie that is still shining.

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Shrapnel From Relatively Recent Supernovae Found in the Earth’s Crust

A Japanese oil exploration company recently dug up some samples from the Pacific Ocean floor and donated them to researchers.  Those researchers, led by Dr. Anton Wallner at the Australian National University, then found the first ever evidence of a plutonium radioactive isotope that originally came from outer space.  Now scientists are trying to understand what could have created that isotope, and another intriguing extraterrestrial one, and what that might have meant for Earth’s cosmic neighborhood a few million years ago.

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