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kordic
2007-Jun-29, 04:35 AM
As I am new here, I am not sure if this is the right type of question to ask in this area. This is more a hypothetical one. Some theorize that Jupiter is a "failed" star, or a brown dwarf if I am correct? If by chance it actually was a star from day one, what would our Solar System be like? Other than being much brighter in the sky, would it's gravity be stronger? This is assuming that it would be the same mass. And how different would life on Earth be? And what about Europa and Titan's composition? It has just crossed my mind a few times, and would appreciate any answers or insight, thanks!

Noclevername
2007-Jun-29, 04:42 AM
As I am new here, I am not sure if this is the right type of question to ask in this area. This is more a hypothetical one. Some theorize that Jupiter is a "failed" star, or a brown dwarf if I am correct? If by chance it actually was a star from day one, what would our Solar System be like? Other than being much brighter in the sky, would it's gravity be stronger? This is assuming that it would be the same mass. And how different would life on Earth be? And what about Europa and Titan's composition? It has just crossed my mind a few times, and would appreciate any answers or insight, thanks!

It would need to be many, many times more massive to become a star. It's also too small for a brown dwarf.

Here's some info:
http://en.wikipedia.org/wiki/Jupiter
http://en.wikipedia.org/wiki/Brown_dwarf
http://en.wikipedia.org/wiki/Star

With the greater mass, Earth & company would have probably been disrupted from forming at all.

01101001
2007-Jun-29, 04:55 AM
You might want to check out topic: A jupiter sun? (http://www.bautforum.com/showthread.php?t=12732)

EDG
2007-Jun-29, 05:32 AM
Well, first everyone needs to ignore how impossible it is to turn Jupiter into a star - the OP isn't asking about that, he's asking "what would the solar system be like if Jupiter always was a star".

We'll call it Lucifer, since that's what Arthur C Clarke called his "ignited Jupiter" in 2010.

For starters, if Lucifer was at 5.204 AU with an eccentricity of 0.0489 (its current orbital parameters), and had a mass of 0.08 solar masses (the minimum to be called a star, so it'd be a M7 to M9 V dwarf star) then it'd orbit Sol in 11.42 years, planets would only be able to orbit within a distance of 2.12 AU from Sol, and planets would be able to orbit Lucifer within a distance of 0.561 AU. And planets could orbit the pair beyond a distance of 10.96 AU from the barycentre of the system.

The barycentre itself would be 0.3855 AU from Sol, and 4.8185 AU from Lucifer. Not entirely sure what that would do to Mercury, given its current distance is 0.387 AU from Sol - I guess it just wouldn't form there?

Anyway. That notwithstanding, the four rocky planets could still form. They'd probably not have an awful lot of volatiles available to form them though since Lucifer would probably turf a lot of those out or evaporate them away (and there's no asteroid belt, or a very thin one maybe beyond Mars).

Noclevername
2007-Jun-29, 05:42 AM
So Earth would probably be a little smaller, much hotter, and a lot drier. Plus its orbit might be a little wonky.

EDG
2007-Jun-29, 05:51 AM
So Earth would probably be a little smaller, much hotter, and a lot drier. Plus its orbit might be a little wonky.

Wouldn't be much hotter - even at a closest approach of about 4 AU from an M8 V star, Earth wouldn't notice any extra heat. If you're at 4 AU from an M 8 V, it's about the equivalent of 178AU from Sol.

sforce21
2007-Jun-29, 06:01 AM
then perhaps we will have a binary star system here and there will be no life on earth?

Noclevername
2007-Jun-29, 06:09 AM
then perhaps we will have a binary star system here and there will be no life on earth?


It would be hard to say. Conditions on Earth might be less conducive to life, at least for complex lifeforms, but it might be possible for life to form and adapt to the harsher conditions. It would most likely be quite different from the types of life that currently exist on Earth.

m1omg
2007-Jun-29, 08:15 AM
We will have less comet/asteroid impacts, a good thing.

astromark
2007-Jun-29, 08:15 AM
This is all a little bit speculative as to what it might be like if.... From my understanding This could not happen as there is not sufficient mass in this solar system to form such a body. Use all the planets moons and other material available outside the orbit of Mars and, you still fail to have sufficient mass to shine. So extra mass would need to be found.

Under the heading of 'What if....'

In his film 2010 the monolith added that mass to Jupiter and 'Presto' It shone. Leaving all the real questions to the orbital mechanics experts. This would look interesting from Earth. I sagest brighter than a full moon but, not so as to be daylight. Best for the fiction writers I think.

(C)Welcome Kordic.:)

EDG
2007-Jun-29, 08:37 AM
I sagest brighter than a full moon but, not so as to be daylight.

The brightest Lucifer would get (if it was an M8 V) is magnitude -12.87, and that's when it's at closest approach to earth (opposition, at 4.2 AU separation). That turns out to be just a bit brighter than a full moon, but only by about 0.4 magnitudes.

So it'd cast shadows, and it'd be bright enough to see by, and screw up the night sky for astronomers while it was up, but won't turn night into day.

It'd make the Moon look a bit interesting - you could have situations where half would be white and half would be red from the light from Lucifer. And you'd get a Flammarion effect where the shadows of the light cast by a white full moon and red Lucifer interacted on the earth (if the moonlight was blocked and Lucifer wasn't, then you'd see a red-tinted shadow. If Lucifer was blocked and the moon wasn't then you'd see a normal dark shadow).

m1omg
2007-Jun-29, 08:57 AM
It would be a beatiful sight

Disinfo Agent
2007-Jun-29, 11:25 AM
I would like to ask another question: How long would a Jupiter star last (be stable)?

In 2010, Clarke suggests it would be many millennia, but then in 2061 he seemed to have changed his mind, and insinuated that Jupiter (Lucifer) would burn out after a thousand years. I got the impression that he had done some new calculations, and revised his scenario to make it more consistent with the physics. (But I always thought a thousand years was ridiculously little time to allow the Europans to evolve and develop a civilization of their own!)

antoniseb
2007-Jun-29, 11:44 AM
I would like to ask another question: How long would a Jupiter star last (be stable)?

I don't know what you are asking. If there was a minimum M8 red dwarf where Jupiter is, it would last a *very* long time (perhaps a trillion years), but it would not be radiating much energy (which is why it could last so long). Odds are it would emit xray flares often enough to make it an undesirable neighbor.

If you are asking about Clark's scenario, in which artificial means are used to shrink Jupiter (a one Jupiter mass object) enough to get it to ignite, and give off enough energy to make Europa a botanical garden, it would only be stable for tens of thousands of years.

Disinfo Agent
2007-Jun-29, 11:48 AM
If you are asking about Clark's scenario, in which artificial means are used to shrink Jupiter (a one Jupiter mass object) enough to get it to ignite, and give off enough energy to make Europa a botanical garden, it would only be stable for tens of thousands of years.I thought a minimal amount of mass was required to trigger fusion... I mean, they must have added some mass to Jupiter, not just made it denser, right?

eburacum45
2007-Jun-29, 11:51 AM
No; making it denser would work fine.

Presumably the Monoliths only made Jupiter dense enough to intiate deuterium fusion, in which case the Jupiter star would be short lived.

It would still be very hot, for a long time, after deuterium fusion ceased, just like brown dwarfs are; it takes a long time for the heat to escape such a large object- and brown dwarfs get heat from gravitational contraction too- presumably so would 'Lucifer'.

Disinfo Agent
2007-Jun-29, 11:57 AM
Well, that adds a new twist to the question. How long would the heat given off by Lucifer be enough to keep the Europans going (assuming no mass was added to Jupiter; I seem to recall that being said in 2010, now)? It's true that they probably wouldn't miss the light, seeing as they'd evolved in a world in the dark to begin with...

eburacum45
2007-Jun-29, 12:31 PM
I wouldn't do it like that at all- very wasteful. Most of 'Lucifer's' hard won artificial fusion would be useless- the light produced would radiate away into cold black space.

Better to extract the deuterium from Jupiter and build tiny suns in orbit around Europa, like lamps they could illuminate the surface itself with a high degree of efficiency. Better still if the hydrogen or helium could be uses for fusion as well; He3 fuses quite well, I hear. Failing that, the mass could be made into black hole energy generators.

Jupiter's mass would produce 1.8x 10e17 black hole energy generators at a billion tonnes each- producing a remarkable amount of power.
see this page for an estimate of how much power...
http://xaonon.dyndns.org/hawking/

Disinfo Agent
2007-Jun-29, 01:46 PM
And how different would life on Earth be? And what about Europa and Titan's composition?In Clarke's scenario, part of Europa's ice sheet would melt, turning into a thick atmosphere and an ocean on the side of Europe facing Jupiter (Europa is tidally locked). The opposite side would also gain an atmosphere, but with ice underneath it. In the twilight zone there would be violent winds and storms.

I expect that Titan, a satellite of Saturn, wouldn't be much affected. Perhaps you meant some other moon.

Io, in Clarke's own expression, would be "even more hellish than now".

Noclevername
2007-Jun-29, 06:01 PM
We will have less comet/asteroid impacts, a good thing.


Not a good thing during planet formation. Afterwards, maybe.

eburacum45
2007-Jun-29, 06:32 PM
This is also being discussed over at the OA yahoo group, where someone has pointed out that Martyn J Fogg suggested stellifying Jupiter by chucking a primordial black hole into it.
Here is the abstract for the paper;
http://adsabs.harvard.edu/abs/1989JBIS...42..587F
Not many details there, but I suspect it would rely on the formation of an energetic accretion disc around the hole.

strangely enough we've been discusing black holes inside planets recently on this board - here (http://www.bautforum.com/showthread.php?t=60749) in fact; the possibility of black holes inside Jupiter is mentioned there.