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Thread: Is Planet Nine almost certain, probable, possible or unlikely?

  1. #31
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    Yet another article on Planet 9. It refers to the article in #25 and has reference to other works being done.

    http://www.centauri-dreams.org/?p=36...auri+Dreams%29

    Considering how long we’ve been thinking about a massive planet in the outer Solar System — and I’m going all the way back to Percival Lowell’s Planet X here — the idea that we might find the hypothetical Planet Nine in just three years or so is a bit startling. But Caltech’s Mike Brown and colleague Konstantin Batygin, who predicted the existence of the planet last January based on its effects on Kuiper Belt objects, are continuing to search the putative planet’s likely orbital path, hoping for a hit within the next few years, a welcome discovery if it happens.

    The duo are working with graduate student Elizabeth Bailey, lead author of a new study being discussed at the American Astronomical Society’s Division for Planetary Sciences meeting in Pasadena, which is occurring in conjunction with the European Planetary Science Congress. The new paper is all about angles and alignments, focusing on the fact that the relatively flat orbital plane of the planets is tilted about six degrees with respect to the Sun. That’s an oddity, and Planet Nine, hypothesized to be about ten times the mass of the Earth and in an orbit averaging 20 times Neptune’s distance from the Sun, just may be the cause.

    The calculations on display in the new paper depict a planet some 30 degrees out of alignment with the orbital plane of the other planets. That can help to explain orbital observations of Kuiper Belt objects, but also the unusual system-wide tilt, which stands out because of the assumed formation of the planets through the collapse of a spinning cloud into a disk and, eventually, a collection of planets orbiting the Sun. We would expect the angular momentum of the planets to maintain a rough alignment with the Sun along the orbital plane.

    Unless, of course, something is disrupting the system. Throw in the angular momentum of Planet Nine, based on its assumed mass and distance from the Sun, and profound effects on the system’s spin become evident, creating a long-term wobble that shows up in the system’s tilt. As Bailey puts it, “Because Planet Nine is so massive and has an orbit tilted compared to the other planets, the Solar System has no choice but to slowly twist out of alignment.”

  2. #32
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    Article on some of the work being done to locate Planet 9.

    http://www.techtimes.com/articles/13...to-find-it.htm

    The Cassini probe takes precise measurements of the position of Saturn as it races around the ringed planet. This data is utilized within a virtual model tracking the exact locations of the largest planets in the solar system. If a large unseen world lurks among the outer planets, the gravitational effects of that body would affect the motions of the known gas giants.

    "For most of the 160 years, astronomers tried to use the positions of the planets themselves to infer the existence of another planet (amusingly: it was the search for this alleged planet that led to the inadvertent discovery of Pluto, which is why the New York Times headline on the day of the Pluto announcement suggests that the planet might be bigger than Jupiter, which it is not)," wrote Mike Brown, a planetary astronomy professor at Caltech who helped propose the idea of Planet Nine.

    As the Juno probe arrives at Jupiter in July 2016, data from that spacecraft will be integrated into the search for Planet Nine.

    On the ground, the Subaru telescope in Hawaii and Chile's Victor Blanco telescope are also being utilized in the search for the distant planet.

  3. #33
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    More evidence on the existence of Planet 9.

    http://www.universetoday.com/133555/...ds-give-clues/

    Last year, Caltech astronomers Mike Brown and Konstantin Batygin found indirect evidence for the existence of a large planet in the outer reaches of our Solar System — likely located out past Pluto — and since then, the search has been on. The latest research continues to show signs of an unseen planet, the hypothetical Planet 9.

    Astronomers using the Gran Telescopio CANARIAS (GTC) in the Canary Islands looked at two distant asteroids called Extreme Trans Neptunian Objects’ (ETNOs), and spectroscopic observations show and their present-day orbits could be the result of a past interaction with a large “superearth”-type object orbiting the Sun at a distance between 300 to 600 AU.

    Researchers say the orbits of asteroids 2004 VN112 and 2013 RF98 suggest that the two were once a binary asteroid which separated after an encounter a large body, with a mass of between 10 and 20 Earth masses.

    “The similar spectral gradients observed for the pair 2004 VN112 – 2013 RF98 suggests a common physical origin,” said Julia de León, the first author of a new paper, and who is an astrophysicist at the Instituto de Astrofísica de Canarias (IAC). “We are proposing the possibility that they were previously a binary asteroid which became unbound during an encounter with a more massive object.”

  4. #34
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    New analysis strengthens the case for planet 9 and also planet 10.

    https://www.eurekalert.org/pub_relea...-nei071217.php

    "Last year, the existence of an unknown planet in our Solar system was announced. However, this hypothesis was subsequently called into question as biases in the observational data were detected. Now Spanish astronomers have used a novel technique to analyse the orbits of the so-called extreme trans-Neptunian objects and, once again, they point out that there is something perturbing them: a planet located at a distance between 300 to 400 times the Earth-Sun separation."

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  5. #35
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    5 reasons why planet 9 exists.

    https://www.jpl.nasa.gov/news/news.php?feature=6964

    It might be lingering bashfully on the icy outer edges of our solar system, hiding in the dark, but subtly pulling strings behind the scenes: stretching out the orbits of distant bodies, perhaps even tilting the entire solar system to one side.

    If a planet is there, it's extremely distant and will stay that way (with no chance -- in case you're wondering -- of ever colliding with Earth, or bringing "days of darkness").It is a possible "Planet Nine" -- a world perhaps 10 times the mass of Earth and 20 times farther from the sun than Neptune. The signs so far are indirect, mainly its gravitational footprints, but that adds up to a compelling case nonetheless.

    One of its most dedicated trackers, in fact, says it is now harder to imagine our solar system without a Planet Nine than with one.

    "There are now five different lines of observational evidence pointing to the existence of Planet Nine," said Konstantin Batygin, a planetary astrophysicist at Caltech in Pasadena, California, whose team may be closing in. "If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them."

  6. #36
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    That's interesting and the five lines of evidence are worth noting, and discussing, probably. Their Planet 9 would cause these things. In georgeeze, they are, I think...

    1) Six objects with orbital alignments not in the ecliptic.
    2) These have odd inclinations.
    3) Very high inclinations, roughly 90o, for other objects should exist and 5 have been found.
    4) The ecliptic plane would shift away from the solar equatorial plane. This is stated to be about 6o, though I think it's closer to 7o (7.25o). [The 6o would fit for Jupiter, and with Saturn (5.5o.]
    5) Retrograde KBOs would exist, and they do.

    It seems that the first two or three could be combined, maybe. I don't know if this would rule-out any other alternative hypothesis than Planet 9, though #4 & 5 might.
    Last edited by George; 2017-Oct-09 at 04:46 PM.
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  7. #37
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    They have found another TNO which strengthens the case for planet 9.

    http://www.dailymail.co.uk/sciencete...OES-exist.html

    Scientists studying eight of the most distant known objects in the solar system have concluded that many of them wouldn’t even exist if their orbits weren’t stabilised by an as-yet undiscovered planet lurking far out beyond the orbit of Neptune.

    The existence of this planet, colloquially known as Planet Nine, has been suspected for several years due to the tilted orbits of these objects, which suggests that they have gravitationally interacted with a planet the size of Neptune several hundred times further out from the Sun than the Earth.

    The bodies in these tilted orbits are a population of large Trans-Neptunian Objects (TNOs), which lie on extremely elliptical orbits out beyond Neptune and Pluto. One of the best known is Sedna, a 1000-kilometre world discovered in 2003.

    But the new work suggests that Planet Nine may also exert a stabilising influence on these bodies, keeping them from being ejected from the solar system by interactions with Neptune, whose orbit they sometimes approach.

  8. #38
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    If this object has an inclined orbit different than those of the rest of the solar system, what would be the explanation for its existence?

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    Quote Originally Posted by bknight View Post
    If this object has an inclined orbit different than those of the rest of the solar system, what would be the explanation for its existence?
    Madigan & McCourt proposed that these objects, along with others with similar orbits, serve each other to maintain the orbits. I think that's the jest of it. It may, however, already been falsified as it is a testable hypothesis, of course. I am curious where this stands. Here is the paper (2016). The Planet 9 hypothesis is the stronger of the two.
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  11. #41
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    The Planetary Society carries an article on the latest status on planet 9.

    http://www.planetary.org/blogs/guest...e-history.html

    So how has the evidence for the proposed Planet Nine held up over the course of the past year? The jury is still out, actually (though the opposing sides in the debate would probably be ready to argue that with me). At the 49th meeting of the AAS DPS (referred to as DPS49 from now on), leading solar system astronomers gathered after several months of back-and-forth debate. I want to highlight two especially notable talks at DPS49. The talks summarized two studies from Summer 2017 that reached completely opposite conclusions regarding the overall importance of observational bias on the observed grouping of distant TNOs. One, conducted by the Outer Solar System Origins Survey (OSSOS), concluded that the observed grouping is due entirely to observational bias. The other, conducted by Dr. Mike Brown (an original proposer of Planet Nine, together with Dr. Konstantin Batygin), concluded that the observed grouping cannot be explained by observational bias. Well now, that’s confusing. Does observational bias completely explain the observed grouping of the most distant TNOs, or does it not? The truth is that we don’t know (again, cue up the arguments by both sides of this debate). We simply don’t have enough data yet!

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  13. #43
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    I don't know any of the mathematical calculations of the discovery, but it seems to me a possibility to back calculate a position and search in that area for this object. Of course it may be that the theory is wrong and nothing exists out there the size/mass of the proposed object.

  14. #44
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    Quote Originally Posted by bknight View Post
    I don't know any of the mathematical calculations of the discovery, but it seems to me a possibility to back calculate a position and search in that area for this object. Of course it may be that the theory is wrong and nothing exists out there the size/mass of the proposed object.
    Isn't that exactly what they are doing? The uncertainties involved mean the area to search is still fairly large, though, and the object is relatively small and terribly faint.

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  15. #45
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    Infrared search comes up negative https://arxiv.org/pdf/1712.04950.pdf

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    Thanks Tom, That's a pretty interesting paper. I guess if Planet 9 is out there, it is hidden against the Milky Way, or at a strangely high ecliptic latitude.
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  17. #47
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    Yet another dwarf planet found that strengthens the case for planet 9.

    https://www.popularmechanics.com/spa...t-planet-nine/

    There might be a large planet lurking somewhere at the very edge of our solar system, and astronomers are hunting for it. While they have yet to find direct evidence of the planet, a recent discovery provides yet more indirect evidence that the planet does, in fact, exist. Astronomers found a small solar system body with a strange orbit that they say can only be explained by another, bigger planet hiding out there somewhere.

    Astronomers have speculated for a few years that a ninth planet may be orbiting the sun at a great distance, and have spent the past few years searching for it. They first started the hunt back in 2016 after looking at a handful of distant solar system objects and noticing something strange. These objects, all orbiting further away than Pluto, had something similar in common: they orbited the sun at a distinct angle from all of the inner planets.

  18. #48
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    I have suggested elsewhere that star trail images could show distant objects by occutations. It is an idea whose time has come I think with modern electronic cameras. It would be a long term project but the area of sky to be searched is coming down I understand. So come on, kudos fame and possibly fortune awaits.

  19. #49
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    Quote Originally Posted by peteshimmon View Post
    I have suggested elsewhere that star trail images could show distant objects by occutations.
    That's a clever idea, but I have strong doubts about its practicality. If the stars trail slowly, then the occultation's signal is smeared out and covered by light from the moments before and after it. If the stars trail too quickly, then only a few, very bright stars will yield signals.

    I suggest you work out the details for a trial system before you push the idea too hard.

    Oh, and with the coming age of fast readout CMOS devices, it seems much easier to just take lots and lots of short exposures, with no trailing.

  20. #50
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    The idea is already in use for predicted consultations for known asteroids and TNOs and it was one of the things I regularly did when I was active in Uppsala Amateur Astronomers. The two main problems are limited sensitivity and overlapping star trails limiting the exposure time. Automating the data reduction would also be very tricky.

  21. #51
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    I tried to find the cold trap distance for hydrogen and it's possible tie to P9, but failed, though I'm struggling with th internet while on vac. I stumbled on the thermal equilibrium equation (solar heat in, BB radiation out). This simplistic equation yields gaseous hydrogen freezing at very roughly 450 AU. Solids, of course, likely facilitate large body formation.

    Is there any mention of this?
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  23. #52
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    Quote Originally Posted by George View Post
    I tried to find the cold trap distance for hydrogen and it's possible tie to P9, but failed, though I'm struggling with th internet while on vac. I stumbled on the thermal equilibrium equation (solar heat in, BB radiation out). This simplistic equation yields gaseous hydrogen freezing at very roughly 450 AU. Solids, of course, likely facilitate large body formation.

    Is there any mention of this?
    If P9 is a rocky super-Earth, about 5 Earth-masses, as proposed, it would have formed much further in than its current position. I'm guessing that means it won't have much free hydrogen to start with.

    If it's a mini-Neptune, Neptune has methane its atmosphere (boiling point 109K at 1 atm) and Uranus also has hydrogen sulphide in its atmosphere (BP. -60 degrees C). In other words they have internal heat which volatilises things that ought not to be gases at their distance from the sun.

    it's an interesting point though, I've not seen anything which models the possibilities for this planet in much detail. Wikipedia says its surface temperature should be 47K, above the boiling pt. of hydrogen.

  24. #53
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    Perhaps it's too speculative at this point. Much more is understood for the snow line for water, which is at ~2.8 AU from the thermal equation and between 2.5 to 3 AU from studying hydration in meteorites. The water gasses would turn to ice, accumulate, form planetismals, resist outward migration and help form, perhaps, the gas giants. The methane snow line is just past Pluto, ~48AU.

    Of course, as noted, planetary migrations make things complicated, but I wonder if at 500 or 600 AU any planetary dancing would occur, thus giving P9 a fixed residence? Massive stellar neighbors may have moved more than its furniture, however, causing giving the predicted inclination.

    https://arxiv.org/abs/1206.0738. Pgs. 6 & 7
    Last edited by George; 2018-May-21 at 06:06 PM.
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  25. #54
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    I came back to this forum because I have a bee in the bonnet about trying to get chance occultations of Oort cloud objects and found an old thread through Google. They would be short one second or less so fast star trails would be needed. This possible planet would be easier giving a few minutes blanking out of stars if you catch one. It would surely be a nice project for groups around the World to cooperate on. Yes there are details to consider but I am sure it is possible.

  26. #55
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    I think you are seriously overestimating the the limiting magnitude, angle of coverage and probability of an occultation of any affordable system. However an occulatation of a big TNO would be several minutes long (see the June 2015 Pluto occultation) so the best bet would be to pick it up as a side effect of using something like the Large Synoptic Survey Telescope (LSST) to survey the sky.

  27. #56
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    Quote Originally Posted by glappkaeft View Post
    I think you are seriously overestimating the the limiting magnitude, angle of coverage and probability of an occultation of any affordable system.
    The designers and users of the TAOS system -- based on relatively small ground-based telescopes which performed a search for small Kuiper-belt objects via occultation -- managed to put together a system which set some limits on the population of KBOs. See http://iopscience.iop.org/article/10.1086/597516/meta

  28. #57
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    I don't know about the star trails method, but if this planet exists it has probably been "detected" many times in the various IR sky surveys.

    So I guess another possibility is a search algorithm that is capable of finding it amongst everything else that is going on. For example, the attempt using WISE images excluded the galactic plane because it was just too crowded.

    Any mileage in that?

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    I remember reading about a computer simulation that explained the retrograde motion of Triton, origin of Pluto and some other stuff. But the mass of the distubing object was not more than five Earth masses which is less than expected for this new object. Nevertheless a remarkable extra item of evidence!

  30. #59
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    Quote Originally Posted by peteshimmon View Post
    I remember reading about a computer simulation that explained the retrograde motion of Triton, origin of Pluto and some other stuff. But the mass of the distubing object was not more than five Earth masses which is less than expected for this new object. Nevertheless a remarkable extra item of evidence!
    I think anything over this mass is excluded by existing search results. For example WISE would've detected a Jupiter to 1 light-year and a Neptune to a great many AU. The working hypothesis seems to be it is a super-Earth.

  31. #60
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    Popular Science carries an article on the possibility of Planet 9 and maybe 10 and 11 as well.

    https://www.popsci.com/kuiper-outer-solar-system

    In 1992, the discovery of a small object unlocked a big secret: that the solar system was far more vast than we’d ever imagined. Before, we’d only confirmed the existence of lonely, strange, cold Pluto, in a region of space called the Kuiper Belt. The Kuiper Belt is a grouping of icy objects located in an area just outside the orbit of Neptune—like a colder, more watery asteroid belt. Up until 1992, it had been strictly theoretical because no one had observed anything beyond Pluto. The discovery of 1992 QB1 marked only the second time an object in the Kuiper Belt had been found. In the next few years, discoveries of these small, cold worlds snowballed—80+ were found between 1992 and 1999, and hundreds are known today. With the outer solar system surveys at Mauna Kea and La Palma observatories in the 1990s, we finally began to unlock the “third zone” of the solar system as something more than theoretical.

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