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Fraser
2005-Mar-03, 06:31 PM
SUMMARY: Astronomers have found a core burning star, like our own Sun, that's only 16% larger than Jupiter; although, it has 96 times as much mass. The observations were made using the European Southern Observatory's 8.2m VLT Kueyen telescope in Chile. Astronomers watched tracked 60 stars which were known to have a regular dip in brightness, when a dimmer object was passing in front. This survey found 7 of these low mass stars which eclipsed their brighter companion.


View full article (http://www.universetoday.com/am/publish/jupiter_sized_star.html)

What do you think about this story? Post your comments below.

VanderL
2005-Mar-03, 06:52 PM
Great story Fraser,

Several questions come to mind; how does this "stellar gnome" produce it's light? How can such a small star can pack that much mass, does it have a solid core? Now we see that some stars are smaller than known planets, doesn't it mean trouble for the current fusion model?

Cheers.

Erimus
2005-Mar-03, 07:16 PM
^
My understanding is that because of their lesser mass, small stars have to compress their interiors more to generate the heat necessary to start fusion--hence, their density. They almost certainly don't have solid cores.

Brown dwarfs form when the protostar's mass is too low to heat up its core to the fusion point, no matter how densely it's compressed. Actually, the answer is probably a little more complicated than that--IIRC, brown dwarfs are somewhat degenerate, which is why adding mass to them causes them to shrink rather than grow, which is similar to the situation with degenerate white dwarfs.

antoniseb
2005-Mar-03, 08:28 PM
Originally posted by VanderL@Mar 3 2005, 06:52 PM
1. How does this "stellar gnome" produce it's light?
2. How can such a small star can pack that much mass?
3. Does it have a solid core?
4. Now we see that some stars are smaller than known planets, doesn't it mean trouble for the current fusion model?
1. It produces light from the heat of collapsing. Similar to the heat that is produced when a heavy object falls a great distance and lands on something. Eventually it will not be able to produce heat this way, but this is why Jupiter produces more energy than it receives.

2. Compression from all the layers on top. Small red dwarfs and brown dwarfs are all about the diameter of Jupiter. Hotter stars expand out.

3. The general idea is that it has a very dense gas in the core, but it is somewhat degenerate, so it is denser than most solids you are familiar with, so it is hard to say what state it is in.

4. No. For low energy producing stars, this size has always been predicted since the early days of the fusion model. On the other hand, I would think that most alternative theories about sources of stellar energy would have difficulty explaining this.

VanderL
2005-Mar-03, 09:37 PM
Thanks Antoniseb,

Apparently these stars were predicted from the models, but

It produces light from the heat of collapsing
the article states that it relies on fusion just like our Sun. The puzzle to me is that matter that is presumably denser, can also produce fusion in the same way as our Sun.


On the other hand, I would think that most alternative theories about sources of stellar energy would have difficulty explaining this.

Most? I'm aware of only 2 alternatives, and one of those wouldn't have any difficulty with these observations.

Cheers.

Svemir
2005-Mar-04, 10:06 AM
My understanding is that because of their lesser mass, small stars have to compress their interiors more to generate the heat necessary to start fusion--hence, their density
What is a mechanism behind "have to", if we exclude the mass and intelligence (both off wich they don't have).

There are several statements where press and original article differ.
The only argument that this is a star is signature of nuclear fusion (from spectral analysis, I presume).
All other signatures are planetlike.
As I see it, it is a planet, ejected from parent star not so long ago.
Primary star and companion are set (by observers) to have small radii because this will put them closer to synchronisation.
Their photometric observations are not very precise and they admit that.

About the description "conditions in the core are like those in Jupiter".
As we all agree (and thus "know") what are the conditions in Jupiters core!?
I doubt that Jupiters deadly radiation is product of some kind of "gravitationaly induced heating".
Jupiter has solid core, with great quantity of uranium, and it's excess of radiation is due to nuclear fission reactions.
I belive that, the OGLA TR 122's companion, is a young planet with uranium core and outer shells containing lighter elements.
To comfirm or disprove my hypothesis further observations are needed (they will come, I'm sure, this is very interesting system) in gamma rays spectrum.
I presume that their conclusion about sunlike nuclear reactions comes from hydrogen spectral lines from companion.
But, it could be several other things:
hydrogen transported from parent star, microlensning, hydrogen in outermost shell heated from interior (and parent star).




doesn't it mean trouble for the current fusion model?
I don't think this means trouble for current fusion model, but certanly this means trouble for the current binary star (star/planet) formation model.
From non-synchronised eliptical orbit, this system is less then 1 billion years old.
So, "wandering" star is excluded: They came to existence in the same place, only "small" walkabouts are probable.
But, they are so close that colaps of some Hydrogen cloud so close to the existing star is unlikely if not impossible.
So, they are formed at the same time.
One should use great deal of imagination and no less coincidental factors in mathematics to colaps a hydrogen cloud (one or two?), into two (sometimes more) stars orbiting each other so close (as in this story) then, find a supernovae nearby to account for metallicity and prove that this is a rule, since 60% of stars are binary systems.
Even Electric Universe model is superior to current "colapsing everywhere but sometimes" model.
These stars are formed in double layers of galactic plasma.

Or the bigger one gave birth to the smaller one.

antoniseb
2005-Mar-04, 11:58 AM
Originally posted by Svemir@Mar 4 2005, 10:06 AM
Jupiter has solid core, with great quantity of uranium, and it's excess of radiation is due to nuclear fission reactions.
Hi Svemir,

Your post is full of odd unsupportable statements. This one about Jupiter's Uranium core is the wackiest. Where did that much Uranium come from?

While we're on the subject, how did a star manage to eject something 100 times as massive as Jupiter into a circular orbit?

Who ever said that Jupiter's 'deadly radiation' came from Jupiter. It comes from the Sun, and is concentrated by Jupiter's magnetic field.

dave_f
2005-Mar-04, 02:56 PM
Degenerate matter is kinda interesting.... it's the reason gas giants don't get much bigger than Jupiter; they just get more dense, because degnerate matter tends to become more and more compact the more you add to it. I can't remember where I read it but they were comparing sizes between Jupiter and a typical brown dwarf and Jupiter was actually bigger!

Degenerate matter occurs when the gravitational force in large bodies like Jupiter overcomes the electromagnetic force responsible for keeping all those atoms and ions from squeezing too closely together. White dwarfs and neutron stars are made almost entirely made of degenerate matter. The cores of Jupiter-sized planets and brown dwarfs are also degenerate matter.

They talked about the atmosphere in this small star in the article. Since the amount of fusion going on is small, does it mean the surface of this star more closely resembles that of the Sun, or that of Jupiter (or something completely different)? It's too bad these things are too far away to take detailed pictures of them...

yet.

;)

VanderL
2005-Mar-04, 05:41 PM
Degenerate matter occurs when the gravitational force in large bodies like Jupiter overcomes the electromagnetic force responsible for keeping all those atoms and ions from squeezing too closely together.

Does this degenerate matter produce the same fusion reaction as normal matter? Why is this degenerate matter inside something with a mass less than 10% of the Sun's? Does the Sun contain degenerate matter as well? It is specifically stated that this object is not a brown dwarf. In the article it is stated that it is a mystery how the Sun-like fusion reactions can take place inside this "stellar gnome".

Cheers.

dave_f
2005-Mar-04, 05:52 PM
Does this degenerate matter produce the same fusion reaction as normal matter?

Only degenerate matter is capable of making fusion happen. Regular matter must become degenerate matter before fusion is even possible (the electromagnetic force keeps the nucleons repelled until gravity can overtake that force and force the nuclei closer together than they normally would be able to).


Why is this degenerate matter inside something wth a mass less than 10% of the Sun's?

There's (supposedly) some at Jupiter's core too, which is a heck of a lot less massive that this baby star.


It is specifically stated that this object is not a brown dwarf.

It's not that far from being one though. A little less mass and this thing would not have lit up at all. The Sun is big because the outer layers get "puffed out" by all that heat generated by fusion. This star doesn't have enough heat to puff out its outer layers.


In the article it is stated that it is a mystery how the Sun-like fusion reactions can take place inside this "stellar gnome".

I'm sure someone some day will do the math and it won't be a mystery anymore. ;)

VanderL
2005-Mar-04, 06:32 PM
Only degenerate matter is capable of making fusion happen

In that case, must a plasma be considered degenerate as as well?

Cheers.

dave_f
2005-Mar-04, 06:39 PM
Originally posted by VanderL@Mar 4 2005, 01:32 PM

Only degenerate matter is capable of making fusion happen

In that case, must a plasma be considered degenerate as as well?

Cheers.
No... in plasmas the energy state of matter is so high the electrons are stipped off of atoms resulting in a cloud of ions (think "fire" in the traditional sense). The positive charges of the nuclei in a plasma however, being positive in charge, repel each other as always. In degenerate matter this repelling is counteracted by other forces like gravity or the strong force. In stars, both gravity and the strong force cause new elements to form via fusion. In white drarfs, no fusion takes place so they are governed primarily by gravity. Neutron stars are almost like huge macro-nuclei, so I really don't know how those things work internally. ;)

Think "compressed beyond imagination" when you think degenerate matter.

VanderL
2005-Mar-05, 08:14 AM
Thanks Dave,

That makes me wonder how we ever hope to accomplish nuclear fusion as an energy source. We only have heat to overcome the repelling charges?

Cheers,

cim
2005-Mar-05, 09:44 PM
if jupiter makes more heat then it gets is it not a star?

dave_f
2005-Mar-05, 10:55 PM
Originally posted by cim@Mar 5 2005, 04:44 PM
if jupiter makes more heat then it gets is it not a star?
Earth makes quite a bit of heat too, but not the way stars make heat (same for Jupiter). A lot of the planets' heat comes from radioactivity (fission) from heavy elementars. Star make it through fusion of lighter elements. That is what seperates the stars and the planets.

To answer your question: no, Jupiter is not a star.

antoniseb
2005-Mar-05, 10:58 PM
Originally posted by cim@Mar 5 2005, 09:44 PM
if jupiter makes more heat then it gets is it not a star?
No. Jupiter is not generating this heat, this is just the heat of formation, still being radiated away, as the planet cools and shrinks.

Planetwatcher
2005-Mar-05, 11:26 PM
Your post is full of odd unsupportable statements. This one about Jupiter's Uranium core is the wackiest. Where did that much Uranium come from?


Could it be that cold fussion reactions are occuring in Jupiter's core? That could account for a high amount of uranium. Otherwise like Anton said, I don't see how a uranium core is possible.


While we're on the subject, how did a star manage to eject something 100 times as massive as Jupiter into a circular orbit?

I don't think an ordanary main sequence star could do the job. Very little short of a super nova, a blue giant star, a red hypergiant, or ergosphere of a black hole would have such a level of power.
And in 2 of those 4, there is no star for the object to orbit.

Svemir
2005-Mar-07, 09:25 AM
Who ever said that Jupiter's 'deadly radiation' came from Jupiter. It comes from the Sun, and is concentrated by Jupiter's magnetic field
My fault. What I had in mind was actually Jupiters huge magnetic field (19 000 times Earth's) and energy needed to sustain it.
To sustain Earth's magnetic field they calculated the energy(heat) needed to be in order of 10-e12 Tw.

My odd proposals come from the idea of Earth's nuclear reactor (I don't know if that was in "Alternative theories") by Marvin Herndon based on Oklo reactor.
IF Earth indeed has nuclear reactor inside which supports it's magnetic field,
then Jupiter as well can have such a reactor inside (and this odd thing around OGLA star. This is a long shot, I must admit:-)).
Georeactor is supposed to deliver about 10-e12 Tw.
Superimposed, Jupiter should have bigger reactor.
What excites me is, that they actually have plans to confirm/dismiss georeactor!
http://www.arxiv.org/PS_cache/hep-ph/pdf/0...401/0401221.pdf (http://www.arxiv.org/PS_cache/hep-ph/pdf/0401/0401221.pdf)
http://www.arxiv.org/PS_cache/hep-ph/pdf/0...409/0409069.pdf (http://www.arxiv.org/PS_cache/hep-ph/pdf/0409/0409069.pdf)
http://www.arxiv.org/PS_cache/hep-ph/pdf/0...411/0411163.pdf (http://www.arxiv.org/PS_cache/hep-ph/pdf/0411/0411163.pdf)



Where did that much Uranium come from?
The same question apply to Earth.
Does supernovae explosion generate elements heavier then iron?
There is a proposal that neutrino flux causes formation of heavier elements (in Sun as well).


how did a star manage to eject something 100 times as massive as Jupiter into a circular orbit?
I take it for granted that mass ejection on planetary scala is possible from Tom van Flandern's site (unstable violent star + large angular momentum) allthough he argues for ejection of planets in pairs.
As I imagine that process, mass ejected from the star is for a momment governed by plasma physics where plasma tend to selforganize ( in thorus) helped by star's magnetic field. As it cools down, recombination takes place, gravity takes over and
a planet companion is formed (or like in this case something between (is it failed star or failed planet or new class of objects?) a star and a planet)
In a such giant Tokamak effects of gravity are negligable,temperatures are tremendous and fusion of "metals" can occur (Uranium maybe?)
In this scenario there is no problem with existence of massive young planets (<100 mio. years old) in the equatorial plain of the star and very close to the parent star.

All these odd theories come from the problems I have with standard accretion theory:
It seems that chemical composition of the planets in Solar system is very simillar,
iron core and lighter elements as we go upwards.
How did mass separation in accretion discs happen i.e. why should we have Hydrogen to Iron composition on Venus distance from Sun and then the same composition on Earth&#39;s distance, and so on, and so on?

If any of these extrem hypothesis of planet ejections (van Flandern, EU, "my own") holds, then we should look at MON V838.
Somethings going on there. Planet or binary star formation or both?
The binary companion is allready discovered, was it there before MON V838 get mad?

I don&#39;t think an ordanary main sequence star could do the job. Very little short of a super nova, a blue giant star, a red hypergiant, or ergosphere of a black hole would have such a level of power.
What do you think about MON V 838, Planetwatcher?




p.s. I&#39;m aware of standard hypothesis of metallic Hydrogen inside Jupiter as a generator of J&#39;s magnetic field.