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.
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.
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.
Quote from: llanitedave on 01/16/2015 04:50 amIf 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.
Mathematics based on orbital perturbation is how Neptune was discovered.
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.
Quote from: Phil Stooke on 01/15/2015 07:06 pmAlso, 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.
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.”
Another of these distant objects has been discovered that is even further out, but haven't yet had a chance to characterise its orbit.QuoteMike 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
Couple of new papers on the possibility of large objects in the far outer solar system.http://arxiv.org/pdf/1512.02650v1.pdfhttp://arxiv.org/pdf/1512.02652.pdfBoth are coming out of observations using ALMA which seems to be at the cutting edge for this kind of research.
Quote from: Star One on 11/11/2015 08:29 pmAnother of these distant objects has been discovered that is even further out, but haven't yet had a chance to characterise its orbit.QuoteMike 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-planetsFYI Mike Brown's twitter handle is @plutokillerHe got a few recent twitter postings about objects in the outer Solar system.
So, what, random comments on news articles are now considered a reliable source?
Hmm, who should I believe? Expert on TNOs or random people with an opinion?Difficult one this.