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ciderman
2010-Nov-18, 07:59 PM
Just spotted this new piece from the beeb about a new hot jupiter exoplanet, in a stellar stream of extragalactic origin.

l was already forming the opinion that planets were fairly plentyful across the universe, but to have found one orbiting a star that we know formed in another galaxy.... wow, that makes my day :)

http://www.bbc.co.uk/news/science-environment-11775803

apologies if that's the UK only link.. I can't recall how to find the international version at the moment, hopefully some helpful person can post it below.

Edit: European Southern Observatory website link

http://www.eso.org/public/news/eso1045/

Hungry4info
2010-Nov-18, 08:51 PM
Also of note, the host star is a horizontal branch star on its way to engulfing the planet. (The ESO link says something to that effect)

Kullat Nunu
2010-Nov-19, 02:03 PM
It should have already engulfed it once when it was a red giant first time.

closetgeek
2010-Nov-19, 02:17 PM
According to one article, they are perplexed as to how this planet formed around this type of star (little to no heavier elements). Is it possible that the planet was rogue and caught by this star's gravity?

m1omg
2010-Nov-19, 05:05 PM
The planet was probably much further from the star originally, as far as Earth or more, but the expanding red giant brought the star's surface closer to the planet.
Considering a red giant is about 1 AU across, this planet was definitely not a hot Jupiter in the past.

m1omg
2010-Nov-19, 05:08 PM
According to one article, they are perplexed as to how this planet formed around this type of star (little to no heavier elements). Is it possible that the planet was rogue and caught by this star's gravity?

I don't think that details like this can be inferred by simple spectroscopy.
It may be that it has many heavy elements, just not on the surface. Or all of them might have been consumed in the planet forming process. Or the planet might be an almost pure hydrogen-helium giant with no or small rocky/icy core. I am tired of many people speaking about the universe like every "assumption" and "theory" that we made up based on our our baby understanding of the universe is truth

closetgeek
2010-Nov-19, 07:58 PM
I don't think that details like this can be inferred by simple spectroscopy.
It may be that it has many heavy elements, just not on the surface. Or all of them might have been consumed in the planet forming process. Or the planet might be an almost pure hydrogen-helium giant with no or small rocky/icy core. I am tired of many people speaking about the universe like every "assumption" and "theory" that we made up based on our our baby understanding of the universe is truth

Are you directing that at me or the writers of the article.


Astronomers were mystified as to how the planet might have formed, since the star contained few elements heavier than hydrogen and helium and planets typically form out of a complex cloud of spinning space rubble.
http://news.yahoo.com/s/afp/20101118/ts_afp/usspaceastronomyeuropegermanychile_20101118204119

I was just wondering based on that.

Kullat Nunu
2010-Nov-20, 10:46 AM
Well, the disk instability model could make this possible. The planet may have formed from a clump of gas in the protoplanetary disk, with very little or not at all heavy elements needed.

m1omg
2010-Nov-20, 11:31 AM
Are you directing that at me or the writers of the article.



I was just wondering based on that.

Not you nor specifically them. Just going against the, in my opinion idiotic, popular notion held by some "scientific" people that we already know everything about the universe just because we know the "basic laws of physics", and that reality must be explained to fit theories instead of obsolete theories trashed in favour of reality.

Also, the dumb "i am not able to made up a model of it, therefore "reality proves it wrong"""style of thinking prevalent in, for example, people who think any alternative life form is impossible. Just because a supercomputer or a scientict cannot imagine how something might be possible it must be impossible, because they said so. It is basically saying "I cannot imagine it, so God/the universe can't do it either". For example the guy in this thread http://s1.zetaboards.com/Conceptual_Evolution/topic/3790830/16/ who thinks the limits for any possible complex moving lifeform are -10 to 70 degrees Celsius and 0.5 to 3 bars of pressure. The fact that there are crabs and worms around boiling hydrothremal vents, that US astronauts breathe pure oxygen at 0.25 bar, that there are fish on the bottom of the Mariana trench living in 1000 bars of pressure does not bother him, he does not even understand that pressure is basically no concern as long as it is equalised with that of the body. There are people who basically desperately want the universe to be boring, so they can squash dreams of people with "No, this is absolutely impossible".

Hypotheses, theories and models are not reality. We shall submit theories to the scrutiny of reality rather than reality to the scrutiny of theories. And just because somebody has made up a theory for everythig does not mean we know everything.

Sorry for a slight offtopic.

Boratssister
2010-Nov-22, 02:20 AM
If this planet came from a dwarf galaxy then how large was this dwarf galaxy and how many stars in our part of the milky way originated from this dwarf galaxy? If this star is only 2000 ly away could sol have originated from this dwarf galaxy and did this dwarf galaxy have a blackhole in its centre?

Hungry4info
2010-Nov-22, 02:57 AM
If this planet came from a dwarf galaxy then how large was this dwarf galaxy and how many stars in our part of the milky way originated from this dwarf galaxy? If this star is only 2000 ly away could sol have originated from this dwarf galaxy and did this dwarf galaxy have a blackhole in its centre?

Wikipedia (http://en.wikipedia.org/wiki/List_of_stellar_streams) claims the Helmi stream to have a mass of 10 to a hundred million solar masses.

There is no eivdence that Sol originated from this dwarf galaxy. These streams have a characteristic motion through space (which is why we know they came from another galaxy). Our sun does not have this motion, and is in fact, fully consistent with being from the Milky Way.