Solar system formation

[LKD]

I was reading this article, and I am having problems understanding the section towards the end.
http://www.physorg.com/news180627887.html

Re:"The intense radiation of this star would have heated up and evaporated anything that was still forming around it," Wolszczan said. "The fact that these dwarfs are still here means that they had to accumulate a lot of material very quickly and be fully formed by the time the star 'switched on.' " A star like BD +20 2457 takes about 10 million years to form and enter the main sequence. As a rough estimate, in order keep up with their parent star, the dwarfs would have to accrue as much mass as the Earth's moon every year."

I can not fathom what they are talking about. Or what process this is that is disrupting gravitational accumulation of material to form planets and the sun.

Could someone explain for my what this is, or where I can find an accurate understandable explanation?

Thanks so much,
L

 

[3488]

Hi LKD.

From where I am sitting, the answer appears to be that the brown dwarves formed quickly, pure and simple. They would have formed around a nucleus of either condensed or collected material (bit like the mystery surrounding Jupiter, did it form around a Super Earth or did it form around a condensation point within the huge annulus of Hydrogen surounding the infant Sun)?

The Brown dwarves in theory would be no different. Once a certain mass was reached their gravitational attraction would be enough to draw in more material quickly (provided it was there, as it was in this case) to become the objects they are before fusion started in the core of the parent Sun.

I do not see any real mystery behind this to be honest with you. The greater the mass of the growing body, the quicker that it can accumulate more mass, because it's Hill Sphere (region of space that the body's gravity is dominant) increases in volume, thus can draw in more material provided it was there to start with.

What may be more unusual with this particular system was perhaps the protoplanetary disk was more massive than 'normal' though really we do not know enough about this to speculate.

This star may well have a vast planetary system as well as the Brown dwarves, though that is speculation on my part.

Andrew Brown.

 

[neilsox]

I understood most of what Andrew Brown typed. He is a good communicator and is almost always correct. I have several issues with the quote from Wolszczan: Dwarf star frequently refers to stars with even more mass than our Sun, as well as low mass stars and brown dwarfs. When a star of many solar mass is about to be born, it produces a very strong solar wind which sweeps the nebula clean. so lesser bodies within about 1% of a light year take on very little additional mass due to lack of material. Perhaps that means a lot of brown dwarfs, but I am guessing. Neil

 

[LKD]

3488: "What may be more unusual with this particular system was perhaps the protoplanetary disk was more massive than 'normal' "

I had a feeling that was the case, or that there was a disturbance in the area, and when this area reformed into this new system, instead of the majority being pulled into 1 massive sun, it broke up into 3 massive bodies of material.

I thank you for your response and am very grateful.

neilsox, That was the part I just can't understand. This solar wind that cuts through the solar system at the ignition point of the sun. What is the process that is involved here? Is this like a large nuclear explosion? I am obviously a little too unfamiliar with the process.

 

[MeteorWayne]

In fact, the evidence indicates that the primary bodies of any stellar system form quickly, with most of the mass in the bodies accumulating with 1 or 2 tens of millions of years. Once the star ignites, the stellar wind and radiation sweep the gas and dust out in very short order, only larger pieces (at least cm sized) will remain.