Rocky planets could have been born as gas giants

Sep 16, 2011 By Nola Taylor Redd
Five baby stars stand out in this image of the Orion Nebula. Four of them have disks of gas surrounding them, where new planets could be forming. Credit: C.R. O'Dell/ Rice University/ NASA

When NASA announced the discovery of over 1,200 new potential planets spotted by the Kepler Space Telescope, almost a quarter of them were thought to be Super-Earths. Now, new research suggests that these massive rocky planets may be the result of the failed creation of Jupiter-sized gas giants.

Most astronomers currently believe are created by a method known as core accretion. Giant disks of gas circle . Grains in these disks bond together to form larger objects known as planetesimals, which collide, creating larger and larger clumps of material. When the clumps reach a , their gravity pulls in gas from the disk around them.

But last summer, Sergei Nayakshin of the University of Leicester in the United Kingdom proposed a new theory for . Known as "tidal downsizing," it works at a faster pace.

In tidal downsizing, a gas disk first forms massive gas clumps farther out in space than where most of the planets discovered so far reside in their solar systems. Left to their own devices, these clumps would cool and contract into very massive (~10 Jupiter mass) planets. Nayakshin showed that during this contraction grow to large sizes and then fall to the center of the gas clump, forming a massive solid core there – the proto-rocky planet within the much more massive gas cocoon.

As planetesimals drift toward their star, they should clear out a path from the gas they move through. Some of that gas helps the planet to grow. Credit: NASA/ JPL-Caltech/ T. Pyle (SSC

"Once you have a core, it may build up an atmosphere around it," Nayakshin explained. "The atmosphere is dominated by hydrogen, but it is much more chemically-rich than the primordial dust material."

The more massive the rocky core, the more massive the atmosphere around it, and it grows with time. Given time, such a mix would result in a giant gas planet with a solid core inside, for example, a super-Jupiter.

However, the surrounding disk pushes the planet in, closer to the star, and there the outer layers of the gas envelope start to be disrupted and actually consumed by the star.

Building on this theory, Nayakshin determined that Super-Earths and other terrestrial planets could, in fact, be the cores of more massive proto-planets that did not have time to mature and were instead robbed of most of their gas by their parent stars. Rocky cores and close atmospheres could survive this disruption process because they are much denser. His paper describing this mechanism appeared in the August edition of the Monthly Notices of the Royal Astronomical Society.

"The remaining core is pretty much a rocky planet, with a mass anywhere from almost zero to ten or so Earth masses," Nayakshin said.

This means the resulting planet could wind up close to their parent star - or farther away, in the area known to as the habitable zone.

Differing from star to star, the "habitable zone" is the area where water can exist as a liquid on the surface of a rocky world. Planets orbiting within this range are considered the most likely to host life.

In this respect, Aaron Boley of the University of Florida says that if planets do form as described by the tidal disruption theory, then planets may be able to form in systems that are unfavorable to the core accretion mechanism, such as in disks with little dust. Although he did not work with Nayakshin, he explored a similar theory early last year.

"I like to think of the mechanisms as opposites," he said. "One is bottom up - core accretion - and the other is top down - tidal disruption."

Boley, who has done extensive research on the formation of gas giant planets and the evolution of planet-forming disks, believes that tidal disruption makes it more likely for life to evolve in a wider variety of stellar systems.

"It is another way Nature can make planets," Boley said.

And more planets mean more chances at life.

This artist's image shows a newly formed planet swimming through the gas and dust surrounding the star. Such a planet might scoop up gas and dust to build an atmosphere, which it could lose as it moves closer to its sun. Thus it could shift from a gas planet to a terrestrial planet. Credit: NASA/ JPL-Caltech

As a new theory, Nayakshin admits that there are many detailed calculations left to perform. He expressed hope that other scientists would help him put his theory to the test.

In last year's paper, Nayakshin expressed the idea that tidal downsizing capitalized on the best of the core accretion model and competing (though more often challenged) model of gravitational instability, while neutralizing the problems in both.

Gravitational instability allows for the rapid creation of planetesimals at a distance from the star, but it doesn't allow them to migrate inward. As such, it can't account for many of the closer planets seen today.

"Tidal downsizing and core accretion are both mechanisms that can form a wide range of planets," Boley said. "They occur during different stages of a proto-planetary disk's lifetime, and are not mutually exclusive."

Core accretion has a difficult time forming planets in more distant orbits over a long period of time. Gravitational instability quickly forms them farther out, where they remain unless they can migrate inward. Tidal downsizing requires that they migrate inward fast enough to have their envelopes removed by tides from their star.

Nayakshin noted that the models contain similar physical steps, but in different proportions.

"In this sense, the final model is likely to be a composite."

Boley expressed interest in watching the new theory develop, and seeing how well it stood against up to the more popular model of core accretion.

“Progress is made in science by taking testable ideas and trying to use them until they are proved wrong,” he said.

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d_robison
5 / 5 (1) Sep 16, 2011
This seems like a fairly obvious theory. One can easily say that some object in space is a failed *insert applicable other object* (i.e. a dwarf planet is a failed planet, a brown dwarf is a failed star). Though I suppose at least the theory is trying to answer the question "Why is object A a failed object B?"
Shootist
4.4 / 5 (7) Sep 16, 2011
Five baby stars stand out in this image of the Orion Nebula. Four of them have disks of gas surrounding them, where new planets could be forming

Nary a spewing neutron star in the mix, eh?
pdfsmail
not rated yet Sep 16, 2011
I knew I should have been some type of astronomer or scientist... I have always believed that is how the planets formed, it seems so obvious to me.... of course that doesn't make it true... but it seems to make much more sense than the disc theory.. who knows maybe both are legitimate ways of creating different rocky worlds (who says there is only one way)?
omatumr
Sep 16, 2011
This comment has been removed by a moderator.
CHollman82
3.5 / 5 (6) Sep 16, 2011
Something cannot fail if it had no intent...
rawa1
2.6 / 5 (5) Sep 16, 2011
It's interesting most of planets in solar system are supposed to have rocky & iron core of the roughly same size. It seems, they collected their hydrogen and lighter elements in secondary process.

http://www.wired....nasa.jpg
d_robison
not rated yet Sep 16, 2011
Something cannot fail if it had no intent...


fail·ure
n.
1. The condition or fact of not achieving the desired end or ends: the failure of an experiment.
2. One that fails: a failure at one's career.

3. The condition or fact of being insufficient or falling short.<--------------------------------------- this is the context that scientists use to describe "failed" objects. (i.e. the object A has failed to become object B, this requires only a conscious observer of any object, regardless if it is conscious or not.

4. A cessation of proper functioning or performance: a power failure.
5. Nonperformance of what is requested or expected;
6. The act or fact of failing to pass a course, test, or assignment.
7. A decline in strength or effectiveness.
8. The act or fact of becoming bankrupt or insolvent.
d_robison
not rated yet Sep 16, 2011
sorry double post.
Phideaux
not rated yet Sep 16, 2011
How can a rocky planet have a mass of almost zero Earth masses?
Nanobanano
3.3 / 5 (6) Sep 16, 2011
How can a rocky planet have a mass of almost zero Earth masses?


Asteroids, moons, dwarf planets, proto-comets

Sheesh...

Moons, dwarf planets, and planets are mostly ambigous, except for the re-defining of the term "planet".

Ganymede is about 2% of the earth's mass.

There's no good reason why an Earth-sized or even Super-Earth sized object couldn't be found orbiting a super-jupiter in another star system...
Phideaux
4 / 5 (1) Sep 16, 2011
I was thinking of mass as amount of material per unit volume, independent of size. Sheesh...
TheGhostofOtto1923
3 / 5 (6) Sep 16, 2011
@QC/nano
There's no good reason why an Earth-sized or even Super-Earth sized object couldn't be found orbiting a super-jupiter in another star system...
-Says the person who is not trained in the subject and has no idea what hes talking about.

Your sickness is extremely uncomfortable to witness. Notice only noobs uprate you? And they only last for a few posts because as you continue to ramble and spout in post after post after post it becomes painfully obvious that there is something WRONG with you.

Whats it going to be today? Another 60 posts of QC stream-of-consciousness? Your brain doesnt stop does it? Thoughts and images and numbers racing, rushing, the compulsion to post them here irresistable... 'must_calculate_must_opine_must_post_cant_stop_now...'
omatumr
1.8 / 5 (9) Sep 16, 2011
It's interesting most of planets in solar system are supposed to have rocky & iron core of the roughly same size. It seems, they collected their hydrogen and lighter elements in secondary process.

http://www.wired....nasa.jpg


I agree.

The iron cores formed first.

They were layered with silicates that formed further from the SN core.

The silicate mantles may have acquired volatile elements that formed even further away.

Plus partial melting of the upper mantle released volatile elements to help form the Earth's atmosphere and oceans.

The noble gas record of the terrestrial planets", Geochemical Journal 15, 247-267 (1981)

www.omatumr.com/a...eGas.pdf
TeKKie
4.2 / 5 (6) Sep 16, 2011
@theghostofotto

I've been reading this site every day for a long time, and i wonder if you realise that you are the 1 who comes across as if you don't know what you talk about simply becaus you always comment on this guy without giving the proof that you do know what you are saying, it's getting anoying...
This site has no prereqs for having done atleast MIT or what ever, so just live with the repsonses and or dispute them please.
I think this would be good for everyone reading all this.
Simply because that would provide more info instead of bashing.
Don't get me wrong i am not saying you are wrong, it's just ethics to keep the site nice to read.
Skultch
4.3 / 5 (4) Sep 16, 2011
Tekkie,

I get your point, but some consider QCs ramblings something not nice to read. You and Otto are essentially complaining about the same thing. The difference is, QC isn't merely discussing and seeking knowledge. He's trying to convince people of things he knows nothing about and Otto's just letting people know that he's not a scientist, since he's trying to come off as one. You should thank Otto for the little slice of knowledge.

btw, thanks to Otto for clueing me in to QCs newest sockpuppet.
TeKKie
3.5 / 5 (2) Sep 16, 2011
I understand, but the ranting on so many topics against it just gets anoying, either just refute the guy or ignore him, i'd say :)
And i just wanted to warn him that his own credibillity is going down for atleast me, by reading all those comments without disprove or prove of him actually knowing better, wich is a shame becaus asfar as i can tell he does know what he's talking about most of the times, when he actually responds instead of just bashing..

Anyways this been anough off topic i'd think.
RealScience
3.8 / 5 (4) Sep 16, 2011
Otto - I agree with you most of the time, but not in this case.
I prefer to rate posts individually, based on the contents of a given post and not based on other posts by the same author (unless the posts are endless repeats like Omatumr's).
In this case Nano's post correctly and reasonably answered a previous poster's question, so the post hardly deserved a 1 whatever you think of Nano's other posts.
People won't learn if you give them the same feedback for a reasonable post as for a nonsense one (they might not learn even with accurate feedback, but that's another matter).
Deesky
5 / 5 (1) Sep 16, 2011
btw, thanks to Otto for clueing me in to QCs newest sockpuppet.

Ahhem!
lairdwilcox
5 / 5 (1) Sep 17, 2011
It makes you wonder what the rocky core of Jupiter would look like if all the gas was blown away.
frajo
3 / 5 (2) Sep 17, 2011
Something cannot fail if it had no intent...

fail·ure
n.
1. The condition or fact of not achieving the desired end or ends: the failure of an experiment.
2. One that fails: a failure at one's career.

3. The condition or fact of being insufficient or falling short.<--------------------------------------- this is the context that scientists use to describe "failed" objects. (i.e. the object A has failed to become object B, this requires only a conscious observer of any object, regardless if it is conscious or not.
...

Thanks for explaining English to non-native speakers. But:

Scientific language - imho - should be precise and free of ambiguity. There are many cases where authors choose a colorful, ambiguous style over a sober style in order to attract a larger lay public.
While this might be seen as advantageous from a merchant's PoV it's certainly disadvantageous from the PoV of enlightenment as we still live in times of widespread superstition.
TheGhostofOtto1923
1 / 5 (1) Sep 17, 2011
In this case Nano's post correctly and reasonably answered a previous poster's question, so the post hardly deserved a 1 whatever you think of Nano's other posts.
There is nothing correct or reasonable about QC presuming to claim:
There's no good reason why an Earth-sized or even Super-Earth sized object couldn't be found orbiting a super-jupiter in another star system...
-when he has neither the training nor the experience to make it. If he is in fact right then it is merely by chance, and he knows more than planetary scientists do.

I don't think QC is rational enough to be an egomaniac.
TheGhostofOtto1923
4 / 5 (4) Sep 17, 2011
I've been reading this site every day for a long time, and i wonder if you realise that you are the 1 who comes across as if you don't know what you talk about simply becaus you always comment on this guy without giving the proof that you do know what you are saying
Read comments in this thread for more typical QC nonsense and what it takes to refute it:
http://www.physor...net.html

1) 60-plus comments/day
2) multiple bans
3) never researches his brilliant ideas to see if they have already been explored
4) refuses to review or acknowledge said explorations by others (including me) even when shoved in his face
5) etc

-Sorry. This just irks me. Is otto too critical always? Perhaps. So what?

And refuting posters is certainly on topic.
TheGhostofOtto1923
1 / 5 (2) Sep 17, 2011
Ganymede is about 2% of the earth's mass.

Mass (Earth = 1) 2.4766e - 02

So he's only off by a factor of 2.5??
RealScience
4 / 5 (5) Sep 17, 2011
Otto - I certainly agree that QC could be annoying and very wrong. I pointed out that QC made basic errors such as using the speed of light as an acceleration, and other silly errors (especially the YEC nonsense). But as with QC, when Nano at least tries to do the calculations I take the time (if I have the time) to correct his mistakes.

And sometimes posts from QC and Nano (who may indeed be the same, and if not are similar), get the math right, and even the interpretation right.
In those cases I give them good marks rather than bad marks.

In this case, 2.4766e-02 is 2.4766%, so Ganymede is indeed 'about 2% of the earth's mass'. 2% is only off by a factor of 1.25, not a factor of 2.5, and it is also rounded to the closest percent so it is correct to the one-place accuracy used.
TheGhostofOtto1923
4 / 5 (4) Sep 17, 2011
I am mathless - I will freely admit this.
And sometimes posts from QC and Nano (who may indeed be the same, and if not are similar), get the math right, and even the interpretation right.
They are 2 in a series of banned iterations of the same person.
In those cases I give them good marks rather than bad marks.
Good for you. I hope you take the time to note when QC gets a very small and simplistic part of a very complex system right - as he quite recently did in trying to stumble through celestial mechanics. If not, youre reinforcing the misconception that he may be some kind of authority which he is not.

OR will you continue to encourage outrageous nonsense like this re vesta:
I don't think "all" of these craters could have reasonably come from collisions, and I'd propose an alternative mechanism: "Hot Springs"...It's large by "asteroid standards," but small by planetary standards. It shouldn't get hit that often...
-In 60 or more posts a day?
RealScience
3.8 / 5 (4) Sep 17, 2011
Otto - Yes, when I have time I certainly point out the nonsense in QC/Nano's remarks.
I have tutored several dozen people through basic physics, so it is hard for me not to 'grade' the posts and correct the answers out of habit.
(Although I often find that you and several others have already done so well enough that anything I say would be redundant.)
gimpypoet
1 / 5 (1) Sep 17, 2011
what, the point of remarks here is ratings? shame on anyone that posts for poularity.i agree the outlandish half-baked fallicies are annoying,but the result is what he wants, which is to keep everyones attention focused on him.ignoring him is simple enough,just scroll past his posts and let the ratings go.he likes negativity so much the sun in his sky is a neutron sun.don't feed him,starve him out.you couldn't prove him wrong,because that is the negativity he seeks.I who havn't commented for all this time,have been reading and watching for as many years as this site has existed and have learned much from all this banter,but ignoring him will end him in our minds.he craves the negativity of your posts because he has driven away all who listened,lets ignor him and he will get his just deserts.noobs will see through his ignorance as he loses the attention he seeks,and if they trust anyone on this site for the gospel truth,they have blinders on anyway.google and wiki as truth is not truth.
frajo
1 / 5 (1) Sep 18, 2011
I who havn't commented for all this time,have been reading and watching for as many years as this site has existed

Profile: gimpypoet, Member since: August 23, 2011, 4:58 pm

I'm interested in your former life.
Noumenon
4.7 / 5 (49) Sep 18, 2011
You don't need to register to read the site.
RealScience
4 / 5 (4) Sep 18, 2011
Gimpy - I ignore most Omatumr posts because they are repeats (only that stupid spam post matches Omatumr in repetition).
Also near the bottom are YEC posters who post non-science and never responds when their posts are refuted.
Also low are the anti-AGW trolls who set up straw-man arguments or claim that a few decades of observation is too short term and then point to a single cold year as proof against AGW.
And equally annoying are anti-technology whiners who think that humans are bad and world would be better off without people.

Next up are posters who are technically savvy but launch personal attacks on posters rather than scientific attacks on posts, and people like Nano/QC who have some idiotic posts but at least try to do the math and sometimes get it right.

But the bulk of the posters and posts deserve great respect.
Some are on one side of AGW or solar or the political spectrum, and some on the other. Some have questions, and others have answers. They discuss science.
macsglen
not rated yet Sep 18, 2011
One thing in particular caught my attention -- quoting from the article:

"However, the surrounding disk pushes the planet in, closer to the star, and there the outer layers of the gas envelope start to be disrupted and actually consumed by the star."

Can someone explain by what force the disc pushes the planet inward? Because, except for this statement, the new idea makes sense to me.
bluehigh
1.2 / 5 (6) Sep 18, 2011
shame on anyone that posts for popularity

-gimpypoet

I agree but there is a small coterie of egocentric dullards that keep blowing smoke out of each others arse.

so it is hard for me not to 'grade' the posts and correct the answers out of habit.

- realscience

What a good example of some arrogant turd that seems to believe he/she has a monopoly on truth and needs to preach belief to others.

Noumenon
4.7 / 5 (49) Sep 18, 2011
One thing in particular caught my attention -- quoting from the article:

"However, the surrounding disk pushes the planet in, closer to the star, and there the outer layers of the gas envelope start to be disrupted and actually consumed by the star."

Can someone explain by what force the disc pushes the planet inward? Because, except for this statement, the new idea makes sense to me.


http://en.wikiped...igration
macsglen
not rated yet Sep 18, 2011
Thanks for the link, Noumenon. It helped a little. Not much, but a little.
PaulRadcliff
not rated yet Sep 18, 2011
You know it all types act as if you actually "know" which planetary formation theories work more often than others, when that would be quite impossible. Meaning, some argue and puff up feathers like some peeing for distance competition. Who has the most unnecessary RAM on their souped up laptop? This site seems to be geared towards amateurs for a slight edutainment upgrade, not peer-review. That would explain all the Climate Change deniers....True scientists don't deny facts or brag about unproven theories.
dtxx
5 / 5 (4) Sep 19, 2011
True scientists don't deny facts or brag about unproven theories.


True scientists don't claim anything about facts, and all theories are by definition unproven. Is there a point somewhere in there?
Pyle
4.2 / 5 (5) Sep 19, 2011
@macsglen:

Noumenon's link,
Thanks for the link, Noumenon. It helped a little. Not much, but a little.
Here's a quick stab at it. The gas disk slows the orbit of the forming planet and as a result the orbit of the planet decays. The author uses the word pushes, but the central mass is really "pulling" the planet in. The gas disk is just slowing the planet down enough to let the central mass pull it a little closer.

On to QC/spectater/nanerbannaner, this iteration is much better than the previous ones. There is obviously something different about him. He is improving. Good on ya mate. RS, good on you too.

Otto, just point him out and let it go. Your global elite conspiracy theory posts are much more entertaining.

On to popularity contests. The idea here, for me at least, is to bounce my ideas off of other people. Its a fun hobby. Better than just reading techie books in a cave like before. Do you know how hard it is to find other people interested in this stuff?
TheGhostofOtto1923
1 / 5 (1) Sep 19, 2011
On to QC/spectater/nanerbannaner, this iteration is much better than the previous ones. There is obviously something different about him. He is improving. Good on ya mate. RS, good on you too.
What??!? What kind of happy pills you on today Pyle? QC went from bible quoting to dry ice at the poles to hot springs on asteroids and celestial mechanics in 1000 numbers or less, in yet MORE posts per day. This is not improvement.
Otto, just point him out and let it go.
Sorry. He must be pointed out and debunked as a public service.
Your global elite conspiracy theory posts are much more entertaining.
You bet - because they are truly grand in Scope, and they ring of Truth. And they have never been seriously debunked. Yay.
Quarl
not rated yet Sep 19, 2011
I'm no scientist, but what's wrong with the idea of an earth-sized or even super-earth sized moon revolving around a super-Jupiter or even another Jupiter? If the barycentre of the two body system lies within the body of one then the second body fulfills the criteria of a moon provided that the first is not a star, right? Besides, the word "planet" seems to be just a term anyway since a dwarf planet is not considered to be a real planet but a dwarf human is a real human. Perhaps I am not seeing this correctly.