What would the initial fusion of a star look like???

Question

Has this been witnessed before in any wavelegnth by humans???

Answer 1

Not that I am aware of.
The initial ignition of a star will happen in its core. It will take some time for the energy to make it's way out, and when does, I do not expect to see a bursting explosion. It is far more likely that what you would see, as a nearby observer, would be a large ball of brightly glowing gas that had been shrinking for some time. Then over a short span (maybe a day or so) the shrinking slows and stops. At the same time, (again maybe anywhere from one hour to several days) the light output increases rapidly getting brighter and brighter. I would liken it to having a light bulb on a dimmer switch and turning up the light from a minumum to full brightness in a matter of a few seconds.

I doubt there will be an explosion per se. There will certianly be an outward radiating stream of matter (stellar wind) but nothing overly spectacular.

If you watched the movie 2010, it is my opinion that that is a little overdramatized. As the protostar shrinks, it would get brighter and brighter, not dimmer and dimmer then explode.

Now if you were observing from within the core of the star, you would see nothing but light. The temperatures necessary for fusion to begin are millions of degrees, and before the temperature ever gets that high, the hydrogen would already be glowing brightly even if it is only hundreds of thousands of degrees.

But if you could ignore the light that is already present, and could see the individual hydrogen nuclei themselves, what you would see happen would look an aweful lot like what you see if you pop popcorn in a transparent dish.

If you are interested in the actual mechanism of fusion, I urge you to google the following topics:

Proton Proton Chain
Triple Alpha Process
C N O Cycle

This is my opinion only. I have never considered your question before. Thanks for making me think about it.

Answer 2

Early fusion in a pre main sequences fuses the deuterium first because this is pretty easy. (Lithium too, but this is present in such a small amount as to not be a significant source of energy.)

There is a SciAm article on this part of stellar evolution.

http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1991SciAm.265...48S

Pre main sequence stars are typically above and to the right of their eventual main sequence location on the Herzsprung Russel diagram (they are cooler, brighter and puffier than they will be once they settle down onto the main sequence.)

Answer 3

Bright. But not so bright as the fusion of a real star.

Answer 4

Bright...
BIG BANG bright !