Newly discovered celestial object defies categories

Jan 08, 2014
This is an image of the ROXs 42B system obtained with the Keck telescope. The star is located in the center of the masked region. ROXs 42Bb orbits at about 150 astronomical units (AU). (1 AU=the distance from Earth to the Sun.) The other object ("c") is a likely unrelated background star. Credit: Thayne Currie

An object discovered by astrophysicists at the University of Toronto (U of T) nearly 500 light years away from the Sun may challenge traditional understandings about how planets and stars form.

The is located near and likely orbiting a very young star about 440 light years away from the Sun, and is leading to believe that there is not an easy-to-define line between what is and is not a planet.

"We have very detailed of this object spanning seven years, even a spectrum revealing its gravity, temperature, and . Still, we can't yet determine whether it is a planet or a failed star – what we call a 'brown dwarf'. Depending on what measurement you consider, the answer could be either," said Thayne Currie, a post-doctoral fellow in U of T's Department of Astronomy & Astrophysics and lead author of a report on the discovery published this week in Astrophysical Journal Letters.

Named ROXs 42Bb for it's proximity to the star ROXs 42B, the object is approximately nine times the mass of Jupiter, below the limit most astronomers use to separate planets from , which are more massive. However, it is located 30 times further away from the star than Jupiter is from the Sun.

"This situation is a little bit different than deciding if Pluto is a planet. For Pluto, it is whether an object of such low mass amongst a group of similar objects is a planet," said Currie. "Here, it is whether an object so massive yet so far from its host star is a planet. If so, how did it form?"

Most astronomers believe that gas giant planets like Jupiter and Saturn formed by core accretion, whereby the planets form from a solid core that then accretes a massive gaseous envelope. Core accretion operates most efficiently closer to the parent star due to the length of time required to first form the core.

An alternate theory proposed for forming gas giant planets is disk instability – a process by which a fragment of a disk gas surrounding a young star directly collapses under its own into a planet. This mechanism works best farther away from the parent star.

Of the dozen or so other young objects with masses of planets observed by Currie and other astronomers, some have planet-to-star mass ratios less than about 10 times that Jupiter and are located within about 15 times Jupiter's separation from the Sun. Others have much higher mass ratios and/or are located more than 50 times Jupiter's orbital separation, properties that are similar to much more massive objects widely accepted to not be planets. The first group would be planets formed by core accretion, and the second group probably formed just like stars and brown dwarfs. In between these two populations is a big gap separating true planets from other objects.

Currie says that the new object starts to blur this distinction between planets and brown dwarfs, and may lie within and begin to fill the gap. "It's very hard to understand how this object formed like Jupiter did. However, it's also too low mass to be a typical brown dwarf; disk instability might just work at its distance from the star. It may represent a new class of planets or it may just be a very rare, very low-mass brown dwarf formed like other and brown dwarfs: a 'planet mass' brown dwarf."

"Regardless, it should spur new research in planet and star formation theories, and serve as a crucial reference point with which to understand the properties of young at similar temperatures, masses and ages," Currie said.

Explore further: Stormy stars? Spitzer probes weather on brown dwarfs

More information: The discovery is reported in a study titled "Direct imaging and spectroscopy of a candidate companion below/near the deuterium-burning limit in the young binary star system, ROXs 42B" which can also be viewed on arXiv.org at arxiv.org/abs/1310.4825 . Currie will present these and other findings at the annual meeting of the American Astronomical Society in Washington, DC this week.

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User comments : 14

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cantdrive85
1.4 / 5 (18) Jan 08, 2014
Newly discovered celestial object defies categories

Such issues arise when theory doesn't match reality, a rampant occurrence in astrophysics.
Returners
1.4 / 5 (10) Jan 08, 2014
Newly discovered celestial object defies categories


Arbitrary categories can produce logical fallacies when they become the basis of divergent theoretical mechanisms.

In any case, a core collapse of any size should be possible from Earth to star size.

If an object which is currently "fully formed" were to pass into a cloud of gas and dust, would it not collapse part of the cloud and pick up much more material?

So an object formed in multiple stages, or from the collision of multiple gas clouds, or even preexisting planets, could easily jump any preconceived barriers between arbitrary categories.

Of course, there's always the possibility that your theory is just completely wrong.

How does it go, "Once you've eliminated the impossible, whatever remains must be the truth."

Therefore theory needs reinterpretation, or even modification if reinterpretation alone isn't enough.

I think "Multi-stage formation" is a good idea in the realm of "re-interpretation".
Q-Star
4.4 / 5 (11) Jan 08, 2014
In any case, a core collapse of any size should be possible from Earth to star size.


Are ya making up these things out thin air? Core collapse (super novae) only occurs in objects with a final mass about 1.4 solar masses. White dwarfs are the UN-collapsed cores of stars with less than this mass. Read up on degeneracy pressure (neutron & electron)..

If an object which is currently "fully formed" were to pass into a cloud of gas and dust, would it not collapse part of the cloud and pick up much more material?


This is very common phenomena. We see it in binaries, it is the mechanism of type Ia SNe. We see it in OB associations where W-R stars shed mass. And in the most massive star known, R136a1 (265 solar masses) which could only have formed from the merger of several massive stars.

This object defies "categorizing" because it is phenomenologically different from other objects. With more data & more observations, it will be placed in an existing or new category.
shavera
5 / 5 (9) Jan 08, 2014
Read up on degeneracy pressure (neutron & electron)..


Really, Returners, you're not entirely lost to the void of crackpottery as some of our famous "skippy"s here. But there is a lot about physics you don't know yet. That's okay. When I was a kid (not implying there's anything immature about this, just my timeline is all) I believed in all sorts of crazy things about the universe because I knew "just enough to be dangerous." So let me provide unsolicited advice:

If you have a theory, be sure that if it was worth considering, someone has already considered it. It may not have been considered because there's some obvious (to those in the field) flaw to it.

But please do read up on what we do know about the universe. The arguments are very solid indeed, and based on observations that may be more or less publicly accessible.
Returners
1 / 5 (5) Jan 08, 2014
Q-Star is once again "reading into" one of my posts something that I did not say.

It amazes me that he actually thought I said the earth would collapse into what a neutron star or black hole?

Get a life and learn to think about the context of what a person is saying, before you start accusing people regarding irrelevant topics.

Since Q-Star and Shavera have the problem of regularly re-interpreting my posts to mean something completely irrelevant to what I said, I am not sure how one is to communicate with them. Its like you say one thing, and then they accuse you of saying something gibberish or unrelated, so maybe they can't read english language, maybe they have a bad translator or something. Google translate probably lost the context of what I wrote, but oh well, not my fault really.
Q-Star
4.8 / 5 (6) Jan 08, 2014
Q-Star is once again "reading into" one of my posts something that I did not say.

It amazes me that he actually thought I said the earth would collapse into what a neutron star or black hole?.


I didn't read into anything ya posted. I even quoted verbatim and in context your own words. I will do so once more.

In any case, a core collapse of any size should be possible from Earth to star size.


Returners, do ya know what core collapse means? If not ya shouldn't have used that term. It has a very specific meaning. If I misunderstood ya, it's not because of reading comprehension abilities, it is because ya use jargon incorrectly.

In any case, a core collapse of any size should be possible from Earth to star size.


I will repeat myself, core collapse can NOT occur with a mass less than 1.4 solar masses. This is NOT new, theoretical or unconventional material in astrophysics, Chandrasekar worked it out almost 90 years ago, he even won a Nobel for the work.
Zephir_fan
Jan 08, 2014
This comment has been removed by a moderator.
Zephir_fan
Jan 08, 2014
This comment has been removed by a moderator.
Zephir_fan
Jan 08, 2014
This comment has been removed by a moderator.
Returners
1 / 5 (4) Jan 08, 2014
The context I was referring to is the core of a cloud collapsing to form a planet. To be sure, a bit different from the supernova core collapse, which I've known about for a very long time; Yet Q-Star accuses me of asserting that something size of the Earth could produce, when I clearly was not talking about a Supernova.

I admit the terminology was not the best, but the term "core" in the context of a cloud or a planet is still just as valid, and I think it should have been clear that I was talking about the formation of a planet, not a star exploding.

Quoting myself:
So an object formed in multiple stages, or from the collision of multiple gas clouds, or even preexisting planets, could easily jump any preconceived barriers between arbitrary categories.


Obviously the context referring back to the planet, or whatever you want to call the unknown object, as discussed in the article.

No mention of a core collapse Super Nova, though that was a creative accusation.
Q-Star
5 / 5 (7) Jan 08, 2014
No mention of a core collapse Super Nova, though that was a creative accusation.


In astrophysics "core collapse" = "Super nova". It is not used in any other context. Planets do not undergo "core collapse". Clouds do not undergo "core collapse". No object less than 1.4 solar masses undergoes "core collapse".

Ya put "core" in there, therefor the problem is yours, not mine, I can't read your mind, only the words ya use. If ya use inappropriate words or jargon, it's your fault ya are misunderstood, because others do not always know what ya "meant to say".

Ya can have the last and every other word on the matter, it's only a big deal because ya can't possibly be wrong. Toot-a-loo.
Returners
1 / 5 (4) Jan 08, 2014
Every planet has a core, and every planet is formed from the collapse of a cloud, of one type or another, according to the standard model of planet formation.

I am not sure what your problem is, nor why you couldn't understand that I wasn't at all talking about a super nova.

it's only a big deal because ya can't possibly be wrong. Toot-a-loo.


When I'm not wrong, I'm not wrong.
Zephir_fan
Jan 08, 2014
This comment has been removed by a moderator.
Returners
2.3 / 5 (3) Jan 08, 2014
Zephir:

It is profanely obvious from the context of my post and the context of the article that I was not at all speaking of Supernovae, and was talking about planet formation via collapse of gas and dust clouds.

Since you didn't use other important words from my post which outline the context more completely, such as "cloud" and "Dust" or even "Planet" you shouldn't expect to find the usage.

Additionally, the order something appears in Google does not always reflect the real relevance of the term or phrase. Two days ago, I was googling a particular phrase, and there were over 3 million "matches". I searched through the first several pages, probably 7 or 8 of them, and then just gave up, as none of the articles were particularly good or relevant, most were on unrelated topics. After refining the search, getting rid of 1 million wrong topics, the first several pages were still mostly unaffected.

Google is sort of like spell check. You can spell correctly, and it still flags things.
Zephir_fan
Jan 08, 2014
This comment has been removed by a moderator.
dav_daddy
3.5 / 5 (8) Jan 08, 2014
Oh for crying out loud! It was obvious he meant to say "core accretion." Why is it some people around here can't wait to bash someone?

Nothing better to do? Desperate need to feel smarter than someone/anyone? Personality disorder?
Mike_Massen
4.5 / 5 (2) Jan 09, 2014
cantdrive85
theory doesn't match reality
time as convergence to improved understanding.
Returners
collapse of any size should be possible from Earth
Collapse into what ? Try a basis in Science not speculation bordering on faith you know something?
Returners
..eliminated the impossible..
Nah, eliminated the improbable, then no matter how impossible the outcome it must be the truth. Eg. No personal deity, if at least baad communication ;-)
Returners
..core of a cloud..
Surely you mean as a result of density fluctuations in conjunction with sufficient gravity ?

Sent this to my son, has just completed Chem Eng but is astronomy geek, his 1st year was 2010 when I was also doing my post grad in food science, fun introducing him to all the gals who wouldn't go out with me ;-)

Universe is VAST, as if equivalent to petri dishes with space as separator & the experiment goes on !

Anyone find ~mag. of (10^60) Factorial ! ?

Where 10^60 is ~carbon compound permutation space
Osiris1
5 / 5 (1) Jan 11, 2014
Of course it could be a wandering object that stayed.
antialias_physorg
1 / 5 (1) Jan 13, 2014
Newly discovered celestial object defies categories

Such issues arise when theory doesn't match reality,

No. Such issues just arise when you try to force an essentally analog universe into a limited number of bins (as there is no 'forbidden' amount of mass a celestial object can have between the ranges of what we call planets and stars). You'll always get borderline cases.

That's not a problem of the theory (as theories don't do this binning.) The binning problem arises from the human need to label stuff. If you see a problem for the theory in this then you don't really know what a theory is.

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