B New theory, our solar system formation, "space bubble"

[Spinnor]

"There are various theories about how the solar system formed, but scientists haven't been able to agree on a single model that explains all the quirks of our corner of space as it exists today. Now, scientists at the University of Chicago have https://news.uchicago.edu/article/2017/12/22/scientists-describe-how-solar-system-could-have-formed-bubble-around-giant-star017-12/uoc-sdh122117.php that explains an enduring mystery about the early solar system. They hypothesize that our solar system formed inside a massive space bubble, which was produced by a star 40 to 50 times the size of our sun. The research was published today in Astrophysical Journal."

From https://www.engadget.com/2017/12/23/solar-system-formation-wolf-rayet-star/

 

[Delta2]

How big exactly was the mother star (Wolf Rayet type star)? IF (I know this is not the case I just say if) its center was the same as the center of our sun would it reach up to where Earth is now?

EDIT: Ok I guess not that big, maybe up to where mercury is...

 

[stefan r]

EDIT: Ok I guess not that big, maybe up to where mercury is...

They can have radius less than the sun. For example WR142, or WR2

 

[Delta2]

They can have radius less than the sun. For example WR142, or WR2

Ok thanks, when I first read the article, I read 50 times bigger than Sun I thought that was referring to the radius of the stars, but I guess it was referring to the total mass of the stars.

Can you help me understand the picture a bit. It says the bubble is in what I identify as the "blue fluid". What the blue fluid is exactly? Also if you can explain briefly what the other components in the picture are, e.g the molecular cloud...

 

[stefan r]

Ok thanks, when I first read the article, I read 50 times bigger than Sun I thought that was referring to the radius of the stars, but I guess it was referring to the total mass of the stars.

Can you help me understand the picture a bit. It says the bubble is in what I identify as the "blue fluid". What the blue fluid is exactly? Also if you can explain briefly what the other components in the picture are, e.g the molecular cloud...

molecular cloud. there are books on this topic.

I think the blue part is just a stellar wind. The graph looks strange on my computer. The colors should be labeled better IMO.

 

[Delta2]

molecular cloud. there are books on this topic.

I think the blue part is just a stellar wind. The graph looks strange on my computer. The colors should be labeled better IMO.

Ok the link for stellar wind says that it is ejected by the upper atmosphere of a star. Let me see If I get the basics of this picture right, the star is represented by the bright little sphere in the center of the picture? Or the star is the whole picture (including the molecular cloud)??

 

[stefan r]

Ok the link for stellar wind says that it is ejected by the upper atmosphere of a star. Let me see If I get the basics of this picture right, the star is represented by the bright little sphere in the center of the picture? Or the star is the whole picture (including the molecular cloud)??

The x and y-axis are labeled R(cm). The video changes the length scale between frames. It it is really 10²⁰ then radius is the image is supposed to be around 100 light years. The top line says "Density, t= ...E⁶" t is rolling forward so I assume time in years. So density must be the colors. The numbers by the color scale change and they change to fast to make sense of them. But they are sequential.

Over 4 million years the star goes from type O to red supergiant and ends and wolf-rayet.

I am a bit skeptical. There is something strange happening at x=0.

 

[jim mcnamara]

I agree with @stefan r - The graphics are confusing, a priori, ...trying to find some clarification.

 

[Bandersnatch]

Here you can see the same simulation running over a longer period of time with some explanations:
http://astro.uchicago.edu/~vikram/Media/bub40.mov
It looks like one of simulations of behaviour of molecular cloud medium under shockwaves from dying stars, like e.g. those seen here:
https://arxiv.org/abs/1111.0012

Here's my best attempt at reading the study:
The graph shows the effects of the stellar wind from a star, in the latter stages of its life, on a molecular cloud in which it is embedded.
The star is too small to show on the scale of the graph.
The extended video above has the bubble expand from approx 20 lyr radius at the end of main sequence, to ~100 lyr by the end of the W-R phase.
The star blows away material in a bubble around itself. This results in a low-density region (in blue) in its immediate vicinity, and a compressed shell (bright yellow) of molecular cloud material (darker yellow). Whenever you see brighter colours (towards the top of the scale), it means there's more material there, and vice versa.
Over time, and as stellar emissions go up, the bubble expands.
Due to various ratios of mass loss and velocity, the flow of material ejected from the star penetrates the shell to varying degrees.
The high-mass loss, high-velocity Wolf-Rayet flows allow the material abundant in the ejecta at this stage of stellar life (specifically, isotopes of aluminium) to penetrate the shell, and the additional compression gives rise to overdense regions in the cloud which will later nucleate new stars. The W-R stage is the last 0.2 million years of the simulation - it's the final, strongest blow seen in the animation.
The ejecta of the subsequent supernova (not shown), which include isotopes of iron, don't penetrate the shell as well, which would explain the relative overabundance of aluminium vs iron we have in our solar system - and this is what the study aims to show.

 

[Delta2]

big thanks @Bandersnatch this answers a lot of questions that had been gathered in my mind.

 

[Ralph Rotten]

So have they been able to locate the remnant of the star that created Sol? Sounds like there should be a smoking hole out there somewhere nearby.

 

[Buzz Bloom]

Hi everyone:

I am unable to make a guess about what I should think about the engadget article. I am guessing that the article is NOT in an authoritative peer-reviewed journal. It did say, "The research was published today in Astrophysical Journal."

My impression from the engadget article is that the authors have made a hypothetical proposal for a new model which aims at explaining flaws/weaknesses in previous models dealing with the formation of the solar system. However, there was no discussion there about how the new model might be confirmed or supported by future observations.

If a reader has access to Astrophysical Journal (I do not), and it presents proposals for methods of confirmation, I would much appreciate seeing a summary of such proposed confirmation methods.

Regards,
Buzz

 

[Ken G]

The ejecta of the subsequent supernova (not shown), which include isotopes of iron, don't penetrate the shell as well, which would explain the relative overabundance of aluminium vs iron we have in our solar system - and this is what the study aims to show.

That would seem to be the key idea. It has been expected for a long time that our Sun formed in a giant molecular cloud, with massive stars evolving first and going supernova, compressing and shredding the molecular cloud, ultimately leading to lots of smaller stars like our Sun. The point of this particular model must be to explain why, if you have supernovae popping off, you end up with lots of aluminum but little iron-60. So that seems to say "Wolf-Rayet stellar wind" rather than just "supernova."

 

[Buzz Bloom]

Hi @Spinnor:

I looked at the list of articles in current The Astrophysical Journal (AJ)

https://iopscience.iop.org/issue/0004-637X/877/1​

I am unable to identify the article referred to in engadget. Since the engadget article did not name any authors of the AJ article, I was unable to search among the listed AJ articles for a name. Can you help me identify the correct article?

Regards,
Buzz

 

[Bandersnatch]

*cough* the thread is almost 2 years old *cough*

 

[Buzz Bloom]

*cough* the thread is almost 2 years old *cough*

Hi Bandersnatch:

Thank you for pointing out my carelessness to me. (One more senior moment.) I would still like to find the AJ article. Can you help me?

Regards,
Buzz

 

[Buzz Bloom]

I found it.
The Astrophysical Journal, Volume 851, Number 2
https://iopscience.iop.org/article/10.3847/1538-4357/aa992ehttps://iopscience.iop.org/article/10.3847/1538-4357/aa992e/pdf