January 21, 2016

New planet in the solar system

Description of the orbit of the new planet and associated objects (Batygin & Brown)
This kind of stuff does not happen every day: a new planet 10 times the mass of Earth has been inferred to exist in the outer reaches of the solar system, but has not yet been directly observed. Or has it?

Konstantin Batygin and Mike Brown have deduced (press release, study) the existence of this object from the trajectory of several anomalous transneptunian bodies of the type of Sedna, whose trajectories seem to orbit both the sun and a distant "super-earth" type planet, so remote that it takes 20,000 years to complete an orbit. 

The Caltech team has not directly eyed the object. However...

A Swedish-Mexican team led by R. Liseau pre-published last month a study where they claimed to have directly spotted a possible outer solar system planet. After some controversy the second version of the pre-pub was withdrawn until further data was collected but the first version is still available online. Another pre-pub paper on the same issue was also authored by W. Vlemmings et al., co-authors of the previous one. 

Direct observation of an object that might be a new planet (Liseau et al.)

I do not know yet if the two studies are convergent or rather they refer to different objects. Neither is fully confirmed as of now in any case but something is almost certainly out there lurking in the depths of the Oort cloud.

19 comments:

  1. This is fascinating stuff indeed!.

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  2. The object observed by Liseau and Vlemmings is probably not Planet Nine.

    Planet Nine is inferred to orbit at approximately 600 AU (aka astronomical units defined as Earth orbits at 1 AU) from the Sun, while the two possibilities identified by Vlemmings are a dwarf planet at 15-25 AU, or an true planet sized object (or larger) at 4000+ AU, neither of which are a fit for Planet Nine at 600 AU.

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    1. Hmmm... a planet sized object and a dwarf planet are not necessarily so different in size. Mercury has just twice the radio of Pluto and hence looks only 4x size like Pluto does at the same distance and albedo, so double the distance, put Mercury in Pluto's orbit of (coincidentally) 30-50 AU, and you have the same visibility.

      Is there any other reason for those narrow reduced ranges? Because planets can vary in size a lot! A rocky planet just 1.55 the radius of Earth would be 10x times as massive but if Planet Nine is gaseous (as they imagine it) then it must be much larger in size and luminosity than Earth, like a small Neptune.

      What I mean is that small changes in the parameters make big changes in the results, so I would have expected a clear cut argument like: it can't be because they are in totally different orbital planes, for example. Else it's like: adjust the parameters a bit and will probably work anyhow.

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    2. The properties do match a Super Earth at 300 AU Andrew, so on that basis it's possible. We only know it's apparent magnitude in 1 band and only have 2 data points to figure out its position and motion. That's not a lot to go on yet.

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    3. Though Maju - to be clear, it's not so much that a dwarf planet and Planet 9 wouldn't look similar with this limited data - it's just that there are probably close to ~10,000 dwarf planets left to be found, and only one Planet Nine. So the odds of this being Planet Nine are extremely low.

      Now, there could be other planet sized objects lurking out there too, but they will still be vastly outnumbered by the smaller objects. So the odds of this being the lucky one is pretty low.

      They will be doing a comprehensive search though. ETA is about 5 years to either find the planet or rule out its existence I believe.

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    4. But... is it in the orbital plane attributed to Planet Nine (which is not the ecliptic but inclined 30 degrees) or not? I was hoping some commentary could clarify this part. If the orbital planes are not coincident, then it's obvious that they are two different objects, right?

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    5. It does have roughly the right inclination, yes. There's a pretty high amount of error in both the Liseau paper and the Planet Nine paper though. 30 degrees inclination isn't unheard of for transneptunian objects either.

      https://en.wikipedia.org/wiki/Detached_object#/media/File:TheTransneptunians_500AU.svg

      It's not so much a question of whether Liseau's object could be Planet 9 as it is a question of why it must be.

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    6. Thank you, Ryan. That narrows the possibilities quite a bit. It might be a coincidence or not but otherwise it would be unrelated almost for sure.

      Why it must be? Dunno. Because every time that Brown discovers something, there's someone else looking at the same thing.

      This is not new: in fact a lot of previous astronomical findings or even technological developments have been reached in parallel by several researchers because, well, the technology has just reached the point where such discovery becomes likely. Uranus was spotted and cataloged by two astronomers before the formal discovery by Herschel (who thought it was a "comet") until Lexell proved him wrong. The discovery of Neptune and Pluto were similarly convoluted... so, if the data fits (and so far it seems so), I'm personally convinced it has a large chance of being the same planet.

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    7. But notice it's a personal conviction, a heartbeat, a strong intuition. I'd bet for it but I don't have any evidence at all: it just follows a logical pattern that has happened often in the past and I like the idea that it is a more or less lucky coincidence.

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  3. The new paper is a stability concerning the orbits of actual dwarf planets. It seems that there is a need of a big body such that their orbits are stable against the interference of jupiter and saturn.

    The orbits of these planets point to a certain direction and have a such harmony that the existence of a new planet is pointed with a likeness of 0.07% of being a coincidence. They do not observe a new planet, but actually say there is a need for one, to keep things stable. The predicted mass is around 10 earth masses, but it is an order of magnitude analysis.

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  4. The also establish the approximate values of the two parameters needed to describe its path in the solar system plane (about 700 AU and 0.6 e, and aligned 180 degrees from other planet's perihelion and in synch with the affected kbos) and determine that its inclination from the solar system plane is modest (probably 30 degrees or less).

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  5. Luis,
    Here something interesting :
    http://rsos.royalsocietypublishing.org/content/3/1/150645

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    1. I'm curious how many of them also have Basque parallels.

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    2. "I'm curious how many of them also have Basque parallels".

      Probably many but doesn't seem like the authors have bothered checking. They seem to be arguing only within the IE frame, what seems utterly confused.

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    3. can you make a post? by pointing which ones may have actually Basque origins?. If you think its worth it of course :) ...

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    4. No, too much work and, as I said, not really my thing. It would take me way too long to research... Stop requesting me to work, I'm lazy and tired and cannot cope with the to-do list I already have. Please stop trying to give me work, give me money instead!

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