Ahhh…
So 3.2M is enough to form a black hole if there’s another appr. 37.8M surrounding it and crushing it into a sufficient density (that of a neutron star).
Or, to put it another way, a 3.2M (more or less) of neutrons will collapse into a black hole.
Of course, you’re not going to get 3.2M of neutrons to just coincidentally come together. It takes 40M of star (and maybe the extra pressure of a supernove explosion) to make it happen.
Peace.
Jeez…read the cites above. While what you say is true you only need roughly 25M of material to get a black hole. 40M doesn’t hurt if your goal is a black hole but you don’t need that much mass to achieve your goal.
No. Per all my linked sites, the absolute maximum neutron star mass is 3.2 solar masses. This necesitates that at some point, an object becomes massive enough to collapse into a neutron star, and this occurs at 1.4 solar masses–the point at which the electromagnetic force is overwhelmed (Achernar). Stars must have much more mass than these minimums, since fusion is ocurring ahd creating heat that counteracts gravitational collapse. When such a high-mass star dies, it goes supernova, expelling well over 98% of its mass. It is the mass that is left over tha determines the star’s final fate.
Once again I guess I shold be more clear than what I most recently posted to jibe with Q.E.D.'s post.
You need roughly a 25 solar mass star to start with before you can expect to see a neutron star or black hole left over. As Q.E.D. mentioned the star will shed most of its mass in a supernova which is why the initial star needs ot be so big…it has to leave enough mass behind to form a neutron star or black hole.
Shedding 98% of its mass seems a bit high though. If you suppose a 50 solar mass star losing 98% of its mass what remains is a 1 solar mass remnant…not enough to get you what you want.
Ummm… you don’t have any linked sites in this thread.
And, I thought that up to 40 solar masses, a star, even a neutron star with way over 3.2 solar masses will just become a brown dwarf. You need over 40 solar masses (usu. with a supernova) to kickstart a black hole.
Peace.
Have you paid any attention to this read or read it at all?
I did link a cite in this thread and it stated that 3.2 solar masses is the maximum size of a neutron star. The same cite stated that you need 25 solar masses to manage a black hole (at the minimum).
A brown dwarf is significantly smaller than anything we are talking about. A brown dwarf is essentially a failed star. Too big to be a planet but not big enough to be a star. They’re about 20-30x the mass of Jupiter which is still MUCH smaller than the mass of our own sun is far too small to form a neutron star much less a black hole.
The only reason you need to start with such a large star to start with, is that a lot of the mass gets blown away in the supernova explosion. All that mass that gets blown away isn’t available for forming our black hole (or whatever other remnant object we want).
But suppose we’ve got a neutron star just sitting around in space. Its supernova was a long time in the past, and it’s settled down peacefully. Now, we slowly add mass to it (preferably iron, so we don’t have to worry about flash-fusion blowing mass off, but hydrogen would work eventually). Eventually, we’ll have a 3.2 solar mass neutron star sitting there, and if we keep on adding mass after that, it’ll become a black hole. You do not need to “kick-start” a black hole, if you have enough mass. The violence of a supernova explosion actually makes it harder to form the hole, not easier, because it blows away so much mass.
Does this really not depend on the material? According to Prialnik, eq. 5.32, the Chandrasekhar mass is given by:
M[sub]Ch[/sub] = 5.83 mu[sub]e[/sub][sup]-2[/sup] M[sub]SUN[/sub]
where mu[sub]e[/sub] is the number of nucleons per electron. For medium-level elements like carbon and oxygen, like you’d get in a white dwarf, it’s 2, which gives 1.46 M[sub]SUN[/sub]. But for hydrogen, mu[sub]e[/sub] = 1.
Great! So you could gather several asteroid belts, extract the iron,carry them to a neutron star, and drop them on to the surface.
At some point you might find that the neutron star starts swelling alarmingly; don’t worry, it is only changing into a