B The Search for a Neutron Star or Black Hole Nearby

[Android17]

If this is true where is the core of that star, either a neutron star or a black hole should exist near by, right?

 

[rootone]

The solar system resulted from the collapse of a cloud of dust and gas, as do other star systems.
That cloud existed first because of there being lots of gas in the galaxy anyway and then some additional contribution of heavier elements from supernovea,
This collapse started to occur about 4,5bn years ago.
There cannot be any evidence of a SN (or several) occurring in the galaxy that long ago.
Black holes and neutron stars are not thought to have much to do with the formation of the Sun or other stellar systems.
There may be neutron stars somewhere in the galaxy whose progenitor SN produced material which now is part of Earth.
If there are, they don't need to be close to where the Solar system is now,

 

[Android17]

The solar system resulted from the collapse of a cloud of dust and gas, as do other star systems.
That cloud existed first because of there being lots of gas in the galaxy anyway and then some additional contribution of heavier elements from supernovea,
This collapse started to occur about 4,5bn years ago.
There cannot be any evidence of a SN (or several) occurring in the galaxy that long ago.
Black holes and neutron stars are not thought to have much to do with the formation of the Sun or other stellar systems.
There may be neutron stars somewhere in the galaxy whose progenitor SN produced material which now is part of Earth.
If there are, they don't need to be close to where the Solar system is now,

Why they don't need to be close? The gases would eventually start to revolve around the nucleus of the dead star, right.. Unless something else pull it away from it?

 

[snorkack]

The solar system resulted from the collapse of a cloud of dust and gas, as do other star systems.
That cloud existed first because of there being lots of gas in the galaxy anyway and then some additional contribution of heavier elements from supernovea,
This collapse started to occur about 4,5bn years ago.
There cannot be any evidence of a SN (or several) occurring in the galaxy that long ago.
Black holes and neutron stars are not thought to have much to do with the formation of the Sun or other stellar systems.

No, but supernovae are relevant.

There may be neutron stars somewhere in the galaxy whose progenitor SN produced material which now is part of Earth.
If there are, they don't need to be close to where the Solar system is now,

Or, indeed, in Milky Way at all.

Why they don't need to be close? The gases would eventually start to revolve around the nucleus of the dead star, right.. Unless something else pull it away from it?

No.
Look around the nearby supernova nebulae.
The youngest nebulae, like Crab which is just 963 years old, are indeed closely connected to their neutron star. But the gases are by the force of explosion traveling directly outwards, not revolving around the pulsar. And the inertia from the explosion far exceeds the feeble gravitational attraction of the pulsar. The gases can only ever be stopped by meeting more interstellar gas in their path, or by gravity of Milky Way.
A bit older? Vela nebula, at 10 000 year old, is very hazy. And Geminga at 300 000 years old is just the Local Bubble.

Now consider that nearby stars do move at some relative speed.
For example, the orbital period of Sun is actually not very well known - it is somewhere between 225 and 250 million years. If it is 225 million years then Sun has made 20 orbits of Galaxy; if it is 250 million years then there were just 18.
If a star has a modest peculiar velocity so that its orbital period is 231 million years while Sun´s is 225 million then in 4500 million years it has made 19,5 orbits of Galaxy while Sun has made 20. So it is now on the opposite side of Galaxy.
But from pulsars, it is known that many pulsars have large peculiar velocities.
Therefore there are good chances that stars which were near Sun during formation of Sun are not near Sun now.

 

[alantheastronomer]

There has been speculation that there was a nearby supernova when the solar system was first formed based on the abundance of Aluminum-26 and it's decay products in meteorites. But that was back in the 80's, I haven't heard much about it since then.

 

[Chronos]

The solar system likely includes remnants from multiple sources - although probably precious little, if any, came from the supernova responsible for the suspected shock wave that triggered collapse of the gas cloud from which the solar system arose.

 

[stefan r]

The solar system likely includes remnants from multiple sources - although probably precious little, if any, came from the supernova responsible for the suspected shock wave that triggered collapse of the gas cloud from which the solar system arose.

How do we measure that?

The rocks in the solar system are somewhat concentrated. A supernova source that increased the cloud's mass by 0.1% should be much more than 0.1% of asteroid mass. At least for average asteroids formed around an average star born in that cloud.

 

[unusually_wrong]

My understanding is that our solar system began as a gas cloud. It began to pull together in an accretion disk, swirling counterclockwise. when the sun was born there was a massive release of energy that blew lighter elements away that formed our Jovian planets/gas giants. The heavier elements stayed closer and formed terrestrial planets. So, our solar system was formed by the birth of our star.

 

[stefan r]

My understanding is that our solar system began as a gas cloud. It began to pull together ...

Right. But there was a shock wave before it collapsed. Short-lived supernova material punched into the material that became asteroids. link.

Turbulence from the shock would have adjusted the timing of stellar collapse. The trigger mechanism.

 

[unusually_wrong]

Right. But there was a shock wave before it collapsed. Short-lived supernova material punched into the material that became asteroids. link.

Turbulence from the shock would have adjusted the timing of stellar collapse. The trigger mechanism.

I watched a documentary (on Netflix) last night about super massive black holes. One of the theories is that the formation of the super massive black hole at the center of galaxies triggered the formation of stars from it's shock wave.

 

[Chronos]

Sorting out the isotope flux from the origins of the solar system is a difficult process. The simpler methods rely on lead isotopes that are relatively easy to date. This is the basis for most age of the solar system estimates. However, this does not account for the various other isotopes found in solar system debris that, to the best of out knowledge, can only be formed by certain kinds of stars of various masses. When you try to date these you get conflicts with the accepted age of the solar system. Some must be much older than the best guess age of the SS and some are certainly much younger. This suggests the solar system consists of a mix of supernova debris dating back millions and even billions of years. You can get a general idea by counting the relative amount of particular isotopes and their probable ages, but, this is not by any means an accurate tally of the total distribution. It is safe to assume counts based on isotopes from planetary cores are less contaminated than those from meteorites, but, we have few if any pristine samples from Earth's core, much less from the cores of other planets and this is what you need to accurately date the solar system.

 

[stefan r]

...we have few if any pristine samples from Earth's core...

If it is in the liquid state radiometric dating does not work. We need samples from the crust. The date given is the time that it crystallized.

 

[Chronos]

Some, but not all dating methods can only measure how long a sample has existed in crystalline form. Others rely on the ratio of parent to daughter isotopes and are insensitive as to whether the sample is or is not crystallized - albeit the test equipment may not be tolerant to the presence of molten magma. A molten sample can simply be permitted to cool and would retain the same isotope ratios as were present in the molten state.

 

[newjerseyrunner]

We are the result of lots of monster explosions. We have to be because only the lightest elements were created in the Big Bang, everything else was created by stars. The first generation of stars were monsters compared to what we have today. They lived fast and died in supernovae, which scattered heavy elements. These were then mixed by the gravitational churning of the galaxy over the next few billion years. Not even the stars the sun was born with are anywhere near us anymore (I think maybe one potential sibling has been found based on it's metal spectrum.) So it's more like thousands of supernovae created the cloud that we were born in.