Igniting Jupiter

[VanderL]

Maybe Jupiter is our binary star yet to FUSE!!!!!!

Or maybe it is our first star that has stopped fusing?

Cheers.

[antoniseb]

Originally posted by VanderL@Mar 25 2004, 02:02 PM
Or maybe it is our first star that has stopped fusing?

Or maybe it is less than two percent the required mass for fusion to ever have started. Not everything we know is wrong.

[VanderL]

Or maybe it is less than two percent the required mass for fusion to ever have started. Not everything we know is wrong.

No argument really, it was just a unfounded remark, but are there other ways to start fusion without high pressure and temperatures. I know that cold fusion (a few years ago it was hot news) doesn't exist, but can't a strong electrical discharge produce fusion products?

Cheers.

[kell]

How can you be sure of Jupiters size,have you actually measured it.Also have you seen a star begin born....more then likely not so how do you know for sure how many more times larger Jupiter would have to be a star?

You don't.The models can be wrong you know.

[antoniseb]

Originally posted by kell@May 1 2004, 02:02 PM
How can you be sure of Jupiters size,have you actually measured it.

Jupiter's mass and diameter have both been measured fairly accurately. This is because things orbit around Jupiter [including the Galeleo Probe for a few years], and we can fairly precisely know the parameters of the orbits. From this we can know the mass down to a tiny fraction of a percent.

If you had disputed how heavy it needed to be to ignite twenty or thirty years ago, you'd have had little argument from observationalists, but over the last few years we've made quite a few observations of minimal weight red dwarfs and brown dwarfs that orbit other stars, and so, we can know their mass as well [but to less precision than we know Jupiter]. Yes you are right that models always need some refining, but observations strongly back up the idea that Jupiter has only one or two percent the mass required to sustain fusion.

[kell]

what would happen if a gas giant crashed into it's star?

[StarLab]

A nice little KABOOOOOOOM!

[antoniseb]

Originally posted by kell@May 1 2004, 03:00 PM
what would happen if a gas giant crashed into it's star?

That's an interesting [even if slightly off topic] question.

The short answer is that if Jupiter were to crash into the sun, the event as seen from Earth would probably be pretty spectacular. There would be some solar flares and coronal mass injections somewhat larger than the biggest we've ever seen. The sun's magnetic field would be visibly disturbed. The helioseismic ringing would also show a lot of evidence of the event. There would be detectably more atoms from heavy elements [heavier than Helium] in the photosphere for a while.

Of course the event that somehow takes away all of Jupiter's orbital momentum a year or so before the crash would also be pretty spectaular. If we are lucky, Jupiter's path toward the sun will not take it near enough to Earth to disturb our orbit much.

Over the long term, presuming that most of the mass that gets blasted out of the sun by Jupiter's entry into it falls back in, the sun would have a tenth of a percent more mass than it does now. This is not enough mass to change the spectral type from G2 to G1.