Posted on 01/19/2018 1:38:43 PM PST by Red Badger
These remaining cores of dead stars can only get so massive before they become black holes.
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The subtle difference between when a massive dying star compresses into a core and when it collapses entirely may have been found. In a study published in Astrophysical Journal Letters, researchers at the Goethe University in Frankfurt say they’ve found the dividing line between compact objects called neutron stars and black holes.
When a massive star reaches the end of its life, it goes out with an immense bang called a supernova. From there, one of two known things Can happen: it either becomes a black hole, which has so much gravity not even light can escape, or a neutron star, which is a city-sized corpse of a formerly large star that’s made out of incredibly dense neutron matter.
But astrophysicists have struggled to find out exactly what variations cause a large star to compress into a dense stellar remnant, a neutron star, rather than the inescapable void of matter-eating fury that is a black hole. According to the Goethe researchers, the difference is simple: 2.16 solar masses. Any leftover object after a supernova that is less than 2.16 times the mass of the sun will start a neutron star, while anything more than 2.16 solar masses will become a black hole.
Most neutron stars are between one and two solar masses, and most black holes discovered so far (or at least suspected so far, since we can’t directly see something that gives off no light) are four solar masses or above.
So why is this important? Researchers are still studying the results of a new phenomena witnessed last year called a kilonova. It created ripples in the fabric of space-time that were detected from Earth. While it was widely reported to be a merger of two neutron stars, some researchers aren't sure if the larger object was in fact one of these dense stellar cores. The larger object was estimated to be between 1.36 and 2.26 solar masses, while the smaller was well within the mass range of an average neutron star.
If it is toward the upper end of that mass estimate, then we may have witnessed the merger of a black hole and a neutron star—which could be essential to the research taking place in the wake of the explosion, as astronomers delve deeper into what kind of object is left behind at the center of such an event. A large, unstable neutron star that swiftly became a black hole could have been left behind after the kilonova, if it was a merger of two neutron stars, or an entirely different event could have taken place where a black hole ingested the smaller neutron star. The latter type of event has been identified before, at least tentatively, in 2005.
The Goethe researchers suggest that adding even a little more mass to the object could cause it to collapse into a black hole—however, some researchers have theorized, but never proven, that another type of object exists between the mass of a neutron star and that of a black hole. But with an upper ceiling to neutron star mass determined, we can begin to figure out how a large star truly dies—and what it takes to make a star fully collapse into a light-eating inferno.
Lots of wild claims represented as facts. Settled science or more mathemagic?
Let’s see them put their hypothesis to a falsifiable test.
I thought the existence of black holes was in doubt.
“It created ripples in the fabric of space-time”
Well, get out the old space-time iron and iron it down.
Maybe a little starch would help.
What is the mass limit of crappy countries before they become shitholes?
Okay. Apparently some people are trying to raise some doubt.
As a non-astrophystican, I just watch from the wings.
Still miss that old star field screensaver, though.
1 socialist/communist dictator................
There are some significant questions. One possibility is that a star core collapses to form a black hole so there is an event horizon, but the core is not compacted into zero size. Instead, the core collapses to Planck density (10^96 grams/cm^3) and then rebounds. However, time dilation is so severe near the collapsed core that to an outsider the rebound occurs very slowly. Indeed, the black hole looks stable. You can read about this in several articles on the net about Planck stars. You can also read about quark stars and strange stars that are intermediates between neutron stars and black holes. Some pretty mind blowing stuff there...
Figures don’t lie, but liars figure.
I doubt that they exist, so its settled.
2.16 Obamas.
“I doubt that they exist, so its settled.”
Oh, well, I didn’t realize.
CNN: Physics fat shames Neutron Stars into massive weight loss until they become a racist term.
These space articles give the reader quite a bit of license, dont you think?
This whole article is blatant white-privilege racism using the excuse of “...light not being able to be observed...” as a reason to call a hole in space-time a “black” hole.
In a sphere about 12 miles across. These are some of the most fascinating objects in the universe.
I wonder, if you could ever get close enough to even see one, before this happens:
It becomes something else. The neutrons are smooshed together in the collapse.
It's been known since the 1930s that it's totally dependent on mass, that's not something that was discovered last week. An older book I have that talks about the mathematical derivations (doesn't actually show the math but explains it) says that up to 1.4 solar masses, your star will become a white dwarf. (This is the Chandrasekhar Limit, named after an Indian astrophysicist who derived it it 1930.) From 1.4-3.3 solar masses, your star will become a neutron star. From 3.3 solar masses on, your star will become a black hole. Maybe the difference between the 3.3 and 2.16 solar masses is that 3.3 is for a normally shining star and the 2.16 is after it has exploded in a supernova and blown off some material.
Bottom line: conceptually, there's nothing new here except for a few numbers that are suspect. Must be a slow day at Popular Mechanics. The title Astronomers Find Mass Limit for Neutron Stars Before Collapsing Into Black Holes is a complete crock, this number was known back in the 1930s and was refined in the 1960s when calculating differential equations and integrals with computers became a lot better. These scientists may have tightened up some of the numbers using some new methods but they discovered something new? No, that's a total crock.
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