'Wonders' question

[kris h]

EUREKA !!!!!!

Here's what i think The small stars like our sun when they die dont go

supernova & there shouldn't be enough hydrogen to create new stars

if they did as the reason they die ran out of hydrogen. So only supermassive stars have enough left over matter for new stars to form Ive always wanted to know what went Bang & left all the gases for our star to form approximately 4 billion years ago was there a massive star where our solar system is 5 billion years ago or did the gases travel lightyears from the stars that went supernova.

clear skies

[LukeSkywatcher]

EUREKA !!!!!!

Here's what i think The small stars like our sun when they die dont go

supernova & there shouldn't be enough hydrogen to create new stars

if they did as the reason they die ran out of hydrogen. So only supermassive stars have enough left over matter for new stars to form Ive always wanted to know what went Bang & left all the gases for our star to form approximately 4 billion years ago was there a massive star where our solar system is 5 billion years ago or did the gases travel lightyears from the stars that went supernova.

clear skies

That sounds about right to me. Small stars dont leave enough behind for it to be recycled. HUGE stars do.

I think i just posted something to the contrary. But that sounds about right.

I'm actually finding myself deep in thought tonight about the death and birth of stars. This thread and the latest episode of "Wonders" really has me thinking, wanting to find out more about the science part of astronomy rather then just the visual.

[zcapp96]

That sounds about right to me. Small stars dont leave enough behind for it to be recycled. HUGE stars do.

I think i just posted something to the contrary. But that sounds about right.

Unfortunately this is not the case. Think of a star as a petrol tanker. If you drive it for long enough it will eventually run out of fuel when the 150 litres in the fuel tank are gone. It doesn't matter that there are several 10's of 1000's of litres of petrol in the trailer because it is not in the right place to power the engine. Same with a star, vast majority of the hydrogen is unburnt because it never gets to the core to power the star.

[LukeSkywatcher]

Unfortunately this is not the case. Think of a star as a petrol tanker. If you drive it for long enough it will eventually run out of fuel when the 150 litres in the fuel tank are gone. It doesn't matter that there are several 10's of 1000's of litres of petrol in the trailer because it is not in the right place to power the engine. Same with a star, vast majority of the hydrogen is unburnt because it never gets to the core to power the star.

OK now THAT really makes sense. So massive stars blow off most of their fuel when they die because it has not been spent on keeping the planet alive. Smaller stars use most of theirs in their life and give off very little?

Isnt that what Kris H just said?

[zcapp96]

OK now THAT really makes sense. So massive stars blow off most of their fuel when they die because it has not been spent on keeping the planet alive. Smaller stars use most of theirs in their life and give off very little?

Isnt that what Kris H just said?

Small stars do not use up most of their fuel, they still only use a small fraction of it.

[LukeSkywatcher]

Small stars do not use up most of their fuel, they still only use a small fraction of it.

Gotcha. Its all relative.

[FraserClarke]

There are two things going on here. Stars only burn a small fraction of their fuel, but they also sequester (sp?) a bigger fraction of material into their stellar remnant (which all produce, with the possible rare exception of pair-production supernovae). For SNe, this is a neutron star or black hole, which is maybe 10-20% of the mass of the progenitor star. So here, 80-90% of the material goes back into into circulation for star formation, the rest is lost to future generations of stars. For lower mass stars, like the sun, about 40-50% of the original star will end up in the remnant white dwarf, with the rest puffed off into space as a pretty planetary nebula. So, after 10 billion years of the Sun's lifetime, about 50% of it's mass will be available again.

As you can see form that, eventually most of the mass in the galaxy will be in the form of stellar remnants, and star formation will fizzle out due to lack of gas. However, the timescales are far longer than the age of the Universe, so we're not into that epoch yet. Most of the solar mass stars ever formed are still shining... Note though that the peak of star formation in the Universe happened about 8 billion years ago, so we're already on a downward trend

[Robthevegetable]

There are two things going on here....

Good explanation, and I had no idea so little of the initial Hydrogen fuel was used during the stars lifetime. The fact that so much Hydrogen is expelled during the stars life and death goes a long way to explaining how the resulting nebula can produce so many new stars.

Thats my question initial answered... I feel well and truly enlightened!!

[meteoriot]

Ah i forgot one thing.

The speed of light.

If it went SN right now, we would not see that for about 650 yrs.

So let's hope it happened about 650 years ago lol.

[Robthevegetable]

I have fingers crossed, although I don't like the thought of crossing them until the supernova happens... I may get cramp!

[sbooder]

I must admit episode two was cracking. It really had me captivated, also baffled too. I will have to watch it again I think...complex stuff!