Author Topic: Dwarf planet discovery hints at a hidden Super Earth in solar system  (Read 111740 times)

Offline Star One

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Some new papers on the search for Trans-Neputian planets. First the source article.

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There could be at least two unknown dwarf planets hidden well beyond Pluto, whose gravitational influence determines the orbits and strange distribution of objects observed beyond Neptune. This has been revealed by numerical calculations. If confirmed, this hypothesis would revolutionize solar system models. Astronomers have spent decades debating whether some dark trans-Plutonian planet remains to be discovered within the solar system. According to scientists not only one, but at least two planets must exist to explain the orbital behavior of extreme trans-Neptunian objects.

http://www.sciencedaily.com/releases/2015/01/150115083036.htm

Heres one paper.

http://m.mnras.oxfordjournals.org/content/446/2/1867

Here is the other.

http://m.mnrasl.oxfordjournals.org/content/443/1/L59

Interesting abstract.

Quote
The existence of an outer planet beyond Pluto has been a matter of debate for decades and the recent discovery of 2012 VP113 has just revived the interest for this controversial topic. This Sedna-like object has the most distant perihelion of any known minor planet and the value of its argument of perihelion is close to 0°. This property appears to be shared by almost all known asteroids with semimajor axis greater than 150 au and perihelion greater than 30 au (the extreme trans-Neptunian objects or ETNOs), and this fact has been interpreted as evidence for the existence of a super-Earth at 250 au. In this scenario, a population of stable asteroids may be shepherded by a distant, undiscovered planet larger than the Earth that keeps the value of their argument of perihelion librating around 0° as a result of the Kozai mechanism. Here, we study the visibility of these ETNOs and confirm that the observed excess of objects reaching perihelion near the ascending node cannot be explained in terms of any observational biases. This excess must be a true feature of this population and its possible origin is explored in the framework of the Kozai effect. The analysis of several possible scenarios strongly suggest that at least two trans-Plutonian planets must exist.
« Last Edit: 01/15/2015 07:05 PM by Star One »

Offline Phil Stooke

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Interesting.  But I must admit I am always sceptical of reports like these.  I certainly wouldn't say "not only one, but at least two planets must exist to explain the orbital behavior of extreme trans-Neptunian objects.".  I would see that as one hypothesis to account for the observations.  The bigger the object is, the more likely we would pick it up from its gravitational effect on the Voyagers and Pioneers (think of the exquisite tracking done to study the so-called Pioneer anomaly) - its different effect on each spacecraft, I mean.   Add IR and other wavelengths, and I'm not convinced such a big object would go undetected.

Also, it is really important to examine the effects of a close flyby of a brown dwarf or similar small object.  What happens to distant orbits if a 100-Jupiter mass object passed 1 lightyear from the Sun a billion years ago? - and then we need to model the whole space, different masses, different distances, different times and speeds etc..  A distant planet might be possible, but I think we need to know a lot more before we assume it 'must be' present.

I expect some of this work has been done but I'm not aware of it.

Offline llanitedave

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If  I understand the current IAU definition of "planet", a Super-Earth located well beyond Pluto would not count as a planet, since at that distance with such a long orbital period, it would not yet have had time over the life of the Solar System to "clear it's orbital zone".

This is one of the weaknesses in that IAU definition.
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Offline Star One

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If  I understand the current IAU definition of "planet", a Super-Earth located well beyond Pluto would not count as a planet, since at that distance with such a long orbital period, it would not yet have had time over the life of the Solar System to "clear it's orbital zone".

This is one of the weaknesses in that IAU definition.

They are going to look rather guilty of a logic fail if a planet larger than Earth is ever discovered out there, but still can't be classed as such because of the vagaries of the definition the IAU want to use as to what is and isn't a planet.

Offline llanitedave

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If  I understand the current IAU definition of "planet", a Super-Earth located well beyond Pluto would not count as a planet, since at that distance with such a long orbital period, it would not yet have had time over the life of the Solar System to "clear it's orbital zone".

This is one of the weaknesses in that IAU definition.

They are going to look rather guilty of a logic fail if a planet larger than Earth is ever discovered out there, but still can't be classed as such because of the vagaries of the definition the IAU want to use as to what is and isn't a planet.

Exactly.  There are some good proposed definitions out there, and I know it's not the most important thing in the world, but I don't think the current definition is really helpful towards advancing the understanding and the science.

The best alternative that I've seen comes from David Russell, here:

http://arxiv.org/abs/1308.0616

It's more genetic and more extensible, and just needs traction, IMO.
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Offline tea monster

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Mathematics based on orbital perturbation is how Neptune was discovered.
« Last Edit: 02/11/2015 03:03 PM by tea monster »

Offline Ben the Space Brit

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I seem to remember reading on Wikipedia (yeah, I know) that the orbits of some of the KBOs, especially Sedna, imply the existence of a whole new family of objects whose average heliocentric distance is out beyond the Kuiper Belt (the so called 'cliff' beyond which it has previously been thought that large planetary rather than cometary objects would not stray) but well short of the inner edge of the Oort Cloud. These objects, if small and terrestrial/ice, would probably be so low brightness that it would only recently have become technically possible to identify them as anything but faint background stars and then track them.
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Offline Comga

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Mathematics based on orbital perturbation is how Neptune was discovered.

It was also how Pluto was discovered but Pluto isnt big enough to cause the perturbations that motivated the search.

Sort of "What Phil Stooke said" above.

And can we leave the definition of "planet" to its own thread(s)?  It pollutes all of these discussions.

Edit: While dynamisists are terrible at writing definitions they are terrific at dynamics. If they have the models it is beyond opinion to dismiss them.
« Last Edit: 03/07/2015 12:37 AM by Comga »
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Offline ChrisWilson68

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Also, it is really important to examine the effects of a close flyby of a brown dwarf or similar small object.  What happens to distant orbits if a 100-Jupiter mass object passed 1 lightyear from the Sun a billion years ago? - and then we need to model the whole space, different masses, different distances, different times and speeds etc..  A distant planet might be possible, but I think we need to know a lot more before we assume it 'must be' present.

A one-time visitor won't align orbits like that.  A one-time visitor will tend to scatter them.  This kind of alignment only happens over a very long term.

Offline clongton

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Also, it is really important to examine the effects of a close flyby of a brown dwarf or similar small object.  What happens to distant orbits if a 100-Jupiter mass object passed 1 lightyear from the Sun a billion years ago? - and then we need to model the whole space, different masses, different distances, different times and speeds etc..  A distant planet might be possible, but I think we need to know a lot more before we assume it 'must be' present.

A one-time visitor won't align orbits like that.  A one-time visitor will tend to scatter them.  This kind of alignment only happens over a very long term.

Without offering any opinion on authenticity, and just to provide an example for discussion, it could be an object similar to ancient Nibiru as found spoken of in the ancient Sumerian astrological tablets. It's a super-earth sized planet, about 4-5x earth, and it has an orbital period of 3,600 earth years. It's perigee is just inside the asteroid belt, its apogee is way out there, and it approaches from under the elliptic at a 30 degree angle to the elliptic. It passes the sun just under the elliptic, passes Mars orbit at the elliptic, continues up past the elliptic and reaches perigee in the asteroid belt, and then drops back below the elliptic. It also orbits clockwise, as opposed to everything else in the solar system, which orbits counterclockwise. It was said to be a captured rouge planet. The tablets say Nibiru stole Mar's air and water on one of its passes. Just saying. I brought this up just to make the point that a super earth doesn't need to be in the elliptic and doesn't need to have a more or less circular orbit. A large captured rouge planet with such orbital parameters could cause the same perturbations and then disappear for a while. It would be really hard to find until it got close.
« Last Edit: 03/07/2015 09:05 PM by clongton »
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Offline Star One

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Further to this topic a new hypothesis on the origin of Sedna.

Grand Theft Sedna: how the sun might have stolen a mini-planet.

http://www.newscientist.com/article/dn27757-grand-theft-sedna-how-the-sun-might-have-stolen-a-miniplanet.html#.VYcnWXB4WrV

Here's a more detailed article on the above.

http://www.centauri-dreams.org/?p=33405
« Last Edit: 06/25/2015 04:01 PM by Star One »

Offline Star One

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Another of these distant objects has been discovered that is even further out, but haven't yet had a chance to characterise its orbit.

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Mike Brown, a planetary astronomer at the California Institute of Technology in Pasadena unaffiliated with the discovery, says that this is the allure of these extreme objects. “They carry the signature of whatever else happened,” he says. But until Sheppard pins down its orbit, V774104 may be interesting—or not, Brown says. “There’s no way to know what it means.” On the other hand, Brown acknowledges that he will have to give up the claim to having discovered the most distant solar system object, which came in 2005 when he found the dwarf planet Eris at a distance of 97 AU from the sun. “I have held the record for 10 years,” he says, jokingly. “I have to relinquish it. So I’m sad.”

http://news.sciencemag.org/space/2015/11/astronomers-spot-most-distant-object-solar-system-could-point-other-rogue-planets

Offline Star One

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Couple of new papers on the possibility of large objects in the far outer solar system.

http://arxiv.org/pdf/1512.02650v1.pdf

http://arxiv.org/pdf/1512.02652.pdf

Both are coming out of observations using ALMA which seems to be at the cutting edge for this kind of research.
« Last Edit: 12/10/2015 09:10 AM by Star One »

Offline Zed_Noir

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Another of these distant objects has been discovered that is even further out, but haven't yet had a chance to characterise its orbit.

Quote
Mike Brown, a planetary astronomer at the California Institute of Technology in Pasadena unaffiliated with the discovery, says that this is the allure of these extreme objects. “They carry the signature of whatever else happened,” he says. But until Sheppard pins down its orbit, V774104 may be interesting—or not, Brown says. “There’s no way to know what it means.” On the other hand, Brown acknowledges that he will have to give up the claim to having discovered the most distant solar system object, which came in 2005 when he found the dwarf planet Eris at a distance of 97 AU from the sun. “I have held the record for 10 years,” he says, jokingly. “I have to relinquish it. So I’m sad.”

http://news.sciencemag.org/space/2015/11/astronomers-spot-most-distant-object-solar-system-could-point-other-rogue-planets

FYI Mike Brown's twitter handle is @plutokiller

He got a few recent twitter postings about objects in the outer Solar system.
« Last Edit: 12/10/2015 05:48 PM by Zed_Noir »

Offline NovaSilisko

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Couple of new papers on the possibility of large objects in the far outer solar system.

http://arxiv.org/pdf/1512.02650v1.pdf

http://arxiv.org/pdf/1512.02652.pdf

Both are coming out of observations using ALMA which seems to be at the cutting edge for this kind of research.

It should be pointed out both of those papers are apparently just submitted, not peer reviewed. Conclusion seems to be to take these both with a fist-sized lump of salt until followup observations are made by others. It was noted on twitter that a serendipitous discovery by ALMA of anything within its small field of view is astonishingly unlikely.

edit: Phil Plait has a good reasonable summary: http://www.slate.com/blogs/bad_astronomy/2015/12/10/extreme_tnos_very_distant_solar_system_objects_may_have_been_found.html
« Last Edit: 12/10/2015 05:45 PM by NovaSilisko »

Offline Star One

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Another of these distant objects has been discovered that is even further out, but haven't yet had a chance to characterise its orbit.

Quote
Mike Brown, a planetary astronomer at the California Institute of Technology in Pasadena unaffiliated with the discovery, says that this is the allure of these extreme objects. “They carry the signature of whatever else happened,” he says. But until Sheppard pins down its orbit, V774104 may be interesting—or not, Brown says. “There’s no way to know what it means.” On the other hand, Brown acknowledges that he will have to give up the claim to having discovered the most distant solar system object, which came in 2005 when he found the dwarf planet Eris at a distance of 97 AU from the sun. “I have held the record for 10 years,” he says, jokingly. “I have to relinquish it. So I’m sad.”

http://news.sciencemag.org/space/2015/11/astronomers-spot-most-distant-object-solar-system-could-point-other-rogue-planets

FYI Mike Brown's twitter handle is @plutokiller

He got a few recent twitter postings about objects in the outer Solar system.

He's also received a degree of flack. Look at the comments on this article about these papers. Especially over his comments about 200,000 objects which he is criticised for making a sweeping rebuttal using a tiny dataset.

http://arstechnica.com/science/2015/12/astronomers-question-claim-of-super-planet-found-at-solar-systems-edge/

Offline NovaSilisko

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So, what, random comments on news articles are now considered a reliable source?

Offline Blackstar

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So, what, random comments on news articles are now considered a reliable source?

Also blogs. Comments on blogs are usually reliable and accurate and unbiased.

Offline Alpha_Centauri

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Hmm, who should I believe? Expert on TNOs or random people with an opinion?

Difficult one this.

Offline Star One

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Hmm, who should I believe? Expert on TNOs or random people with an opinion?

Difficult one this.

A not all the quotes are anonymous.

B You preclude the fact that some of the comments may also be by experts.

C Because of course Twitter is such an effective forum to debate scientific papers in the first place.

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