First evidence discovered of a gigantic remnant around an exploding star

Andromeda galaxy
Credit: CC0 Public Domain

A San Diego State University astrophysicist has helped discover evidence of a gigantic remnant surrounding an exploding star—a shell of material so huge, it must have been erupting on a regular basis for millions of years.

When a white dwarf, the core of a dead star, is in a close orbit with another star, it pulls gas from the other star. The gas becomes heated and compressed, eventually exploding to create a nova. This explosion causes the star to brighten by a millionfold and eject material at thousands of miles per second. The ejected material forms a remnant or shell surrounding the nova.

Allen Shafter and former SDSU postdoc. Martin Henze, along with a team of astrophysicists led by Matthew Darnley at Liverpool John Moores University in England, have been studying a nova in the nearby Andromeda galaxy known as M31N 2008-12a. What makes the nova unusual is that it erupts far more frequently than any other known novasystem.

"When we first discovered that M31N 2008-12a erupted every year, we were very surprised," said Shafter. A more typical pattern is about every 10 years.

Shafter and his team believe M31N 2008-12a has been erupting regularly for millions of years. These frequent eruptions over time have resulted in a "super remnant" surrounding the nova measuring almost 400 light years across.

Using Hubble Space Telescope imaging along with ground-based telescopes, the team worked to determine the chemical composition of the super-remnant and confirm its association with M31N 2008-12a. These findings, published in an article in the journal Nature, open the door to the possibility that this nova and remnant are linked to something more crucial to the universe.

Type Ia supernovae are among the most powerful and luminous objects in the universe and are believed to occur when a white dwarf exceeds its maximum allowable mass. At that point, the entire white dwarf is blown apart instead of experiencing explosions on the surface as other do. These are relatively rare and unseen in our own galaxy since the early 1600s.

Theoretical models show that novae experiencing frequent explosions surrounded by large remnants must harbor massive that are nearing their limit. This means M31N 2008-12a is behaving precisely the way astronomers believe a nova does before it potentially explodes as a supernova.

The discovery of additional large remnants around other novae will help identify systems undergoing repeated eruptions and help astronomers determine how many type Ia supernovae are formed; how frequently they occur; and their potential association with novae like M31N 2008-12a. Type la supernova are a critical part of understanding how the entire universe expands and grows.

"They are, in effect, the measuring rods that allow us to map the visible universe," said Shafter. "Despite their importance, we don't fully understand where they come from."

Shafter and his team are now working to understand if what they observed with M31N 2008-12a is rare, or if there is an unseen population of novae experiencing this as well.


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First evidence of gigantic remains from star explosions

More information: M. J. Darnley et al, A recurrent nova super-remnant in the Andromeda galaxy, Nature (2019). DOI: 10.1038/s41586-018-0825-4
Journal information: Nature

Citation: First evidence discovered of a gigantic remnant around an exploding star (2019, February 17) retrieved 19 July 2019 from https://phys.org/news/2019-02-evidence-gigantic-remnant-star.html
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Feb 17, 2019
And still no signs of Dark Matter or Dark Energy.

The nova that is the subject of the article seems to be consuming more mass as a White Dwarf and then experiences a "hiccup" that removes any excess mass it has consumed. After "regurgitating" its excess mass, it returns to its previous form as a White Dwarf, where it begins again to consume mass from its surroundings until it is ready to become a nova again - where another "hiccup" or "explosion" occurs - ejecting material out again into its neighborhood.
This is a mechanical process that allows the White Dwarf's continued existence.

"When a white dwarf, the core of a dead star, is in a close orbit with another star, it pulls gas from the other star. The gas becomes heated and compressed, eventually exploding to create a nova. This explosion causes the star to brighten by a millionfold and eject material at thousands of miles per second. The ejected material forms a remnant or shell surrounding the nova."



Feb 17, 2019
-contd-
Some humans are like that. Those whom I have read about eat more than they should of one meal, then purge by vomiting the contents of their stomachs - thinking that it will help them to remain slim.
"What fools these mortals be" - Puck, in A Midsummer Night's Dream".

Feb 17, 2019
Why does this not occur in blackholes

SEU "in a close orbit with another star, it pulls gas from the other star. The gas becomes heated and compressed, eventually exploding to create a nova. This explosion causes the star to brighten by a million fold"

This would brighten blackhholes accretion disk

Feb 18, 2019
Why does this not occur in blackholes

SEU "in a close orbit with another star, it pulls gas from the other star. The gas becomes heated and compressed, eventually exploding to create a nova. This explosion causes the star to brighten by a million fold"

This would brighten blackhholes accretion disk

It does happen. There's even articles about it in phys.org: https://phys.org/...ack.html

Feb 18, 2019
"They are, in effect, the measuring rods that allow us to map the visible universe," said Shafter. "Despite their importance, we don't fully understand where they come from."

No, NOT "we don't full understand", try "we currently have absolutely NO clue" instead. Stop using the deceptive euphemism when the truth is so much more elegant. Please.


Feb 18, 2019
Until, cortezz
Why does this not occur in blackholes

SEU "in a close orbit with another star, it pulls gas from the other star. The gas becomes heated and compressed, eventually exploding to create a nova. This explosion causes the star to brighten by a million fold"

This would brighten blackhholes accretion disk

It does happen. There's even articles about it in phys.org: https://phys.org/...ack.html

Until we come to Sagittarius A*, where only blackness is visible
Nor hide nor sight of Sagittarius A* multimillion Ly accretion disc has been seen

Feb 18, 2019
oh deer, cant, you look at the paint on the outside of a house & declaim that since the paint is all you observed?
That coating of paint is all there is that needs to be described.

& you are upset that anyone would make an effort to check out what else there may be to that structure.

How dare anyone contradict your absolute definitive conclusion!

Feb 18, 2019
Star formation is one of the least comprehended phenomenon in astrophysics. Is there a general theory of star formation? No, there is not. There is a number of models based on computer simulations which include supersonic hydrodynamics with non-ideal MHD turbulence influenced by gravity. They include the line and continuum radiative processes of the energy transfer; a number of chemical processes with dissociation, recombination and ionization, with uncertain nomenclature of atoms and molecules, unknown magnetic fields and formation and destruction of dust particles. In addition there is macrophysics that is an environment in the molecular clouds, clumps and cores; inclusion in the multiple systems, collisions among stellar systems; jets and outflows; radiation pressure.
https://www.acade...rvations
https://www.acade...and_Jets

Feb 18, 2019
Until, cortezz
Why does this not occur in blackholes

SEU "in a close orbit with another star, it pulls gas from the other star. The gas becomes heated and compressed, eventually exploding to create a nova. This explosion causes the star to brighten by a million fold"

This would brighten blackhholes accretion disk

It does happen. There's even articles about it in phys.org: https://phys.org/...ack.html

Until we come to Sagittarius A*, where only blackness is visible
Nor hide nor sight of Sagittarius A* multimillion Ly accretion disc has been seen

Actually, the pictures you've seen have lot's of matter filtered out...

Feb 18, 2019
Interesting. One wonders if they will discover a population of novae that eventually turn into SNe.

Feb 19, 2019
I think, very simple process of ignition and light.
It might be possible that, which we are saying a white dwarf is just a source of ignition and any flammable gas coming into contact with this are giving light and the intensity of which depends on the quantity of flammable gas.

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