Posted on 07/16/2021 12:39:08 PM PDT by Red Badger
Astronomers have spotted a star whose shape indicates it will one day be consumed as fuel so a neighbor can become a supernova. The pair are only 1,500 light-years away, so the view from Earth will be spectacular when the explosion occurs. However, at an estimated 70 million years to ignition, there is no guarantee there will be anyone here to watch it.
Astronomers find proto-supernovas all the time. Any star with a mass of more than eight times the Sun will end its life in an enormous explosion, with Betelgeuse being the most famous example. However, these are core collapse supernovas. It's much harder to find Type Ia supernovas before they go off because they originate from white dwarfs, whose faint light is hard to spot unless very nearby.
However, white dwarfs do not explode on their own – to become supernovas they need a neighbor to feed them extra mass, and these stars can be considerably brighter. In Nature Astronomy University of Warwick researchers announced the discovery of one of these companion stars which looks a certainty to be consumed this way.
The stellar pair are named HD265435. We see a subdwarf star with a mass 60 percent that of the Sun twirling around in an orbit lasting just 100 minutes. Although we cannot see the object it is dancing with, the speed of the orbit allows us to calculate that it must have a mass one percent greater than the Sun. Something that massive, but invisible to our telescopes, must be a white dwarf.
White dwarfs are the ultradense remnants of stars that have ceased fusion. Most live out their second lives quietly, slowly cooling. However, those with a close binary companion can meet a different fate. They can either draw material off a neighboring star or merge with it entirely. In either case, on passing 1.4 solar masses, they become unstable and explode as Type Ia supernovas. Besides the spectacular show these give anyone with eyes within hundreds of thousands of light-years, these serve as standard candles, revealing the distance to their home galaxies. This formed the basis of this century's revolution in cosmology, revealing the existence of dark energy accelerating the expansion of the universe.
Despite their crucial importance to science, much about Type Ia supernova remains mysterious – largely because astronomers have not had the chance to study one close-up since the development of modern equipment. "We don't know exactly how these supernovae explode, but we know it has to happen because we see it happening elsewhere in the universe,” lead study author Dr Ingrid Pelisoli said in a statement.
Provided the whole system exceeds 1.4 solar masses, as HD265435 does, an explosion is only a matter of time. Based on the rate they are moving together, Pelisoli and co-authors estimate this will be in 72 million years. By the time this occurs the white dwarf may have captured so much material its companion may no longer be able to achieve fusion, and will be a second white dwarf.
"The more we understand how supernovae work, the better we can calibrate our standard candles,” Pelisoli said. “This is very important at the moment because there's a discrepancy between what we get from [Type Ia supernova], and what we get through other methods,” including measurements of the cosmic background radiation.
Astronomers noticed HD265435 because of the way the subdwarf star was being pulled out of shape by the white dwarf's gravitational field. Theory suggests we should see a lot more pairs like this than we have actually found – Pelisoli noted that even with this discovery, there is a puzzling lack of such known systems, but the discrepancy is now a little smaller.
We only 9 years left. Won’t make 70 million.
One star giving mass to another 1500 lightyears away? What? What moron wrote this? None of this makes any sense. And a white dwarf exploding? No, those cool over billions of years until they stop radiating heat and die of entropy.
“Some day you will find me
caught beneath the landslide...
In a champagne supernover
in the sky...”
The article notes that both stars are about 1,500 light years from Earth.
The two stars orbit each other every 100 minutes. This indicates they are probably very much closer to each other than Mercury is to the sun.
I think you're supposed to call them, 'Little People' now. And you also can't mention race. ;)
What we’re seeing is 70 million years ago. It already went supernova.
Smile. Wait for the flash!
No. About 1500 years ago. It will take about 70,000,000 years to accrete enough of the larger star’s mass onto the white dwarf to cause the blast.
By that time Earth should be a cinder from global warming, if it still exists. I say that because as the warming continues and goes out of control eventually the carbon atoms will start fusing and eventually end up as iron atoms with a blindingly hot atmosphere surrounding it. Getting hotter and hotter without limit. Or so Al Gore says.
“The pair are only 1,500 light-years away”
Thanks for the correction. What we’re seeing is 1,500 year ago. May or may not have gone white dwarf. In cosmic time, 1,500 years ain’t much.
As for here on earth, if the next 1,500 years are like the last 200 years (i.e., since we got the industrial revolution underway), we’ll be 100 million times richer.
file:///Users/cthies/Downloads/3014041ec007.pdf
Think positive!
from EARTH...............
You’re sure it hasn’t changed since post #9?
Probably gotten a little fatter....................
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