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Researchers Find Evidence Of Distant Outer Planet
lilmac
post Sep 2 2016, 03:54 PM
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QUOTE (Gerald @ Jan 20 2016, 07:35 PM) *
That far out the Hill sphere of an object should be rather large. Therfore I'm wondering - provided the analysis isn't based on observational bias - whether there couldn't exist kind of a miniature globular cluster made of planetesimals, or a small version of a protoplanetary disk, of the same mass as the presumed planet, but without having formed an actual planet.
The simulations - as far as I understood - assume a certain point mass, but not necessarily united to one planet.
Or - if there is one population of KBOs - why not a second one, forming a Kozai-like resonance with the observed population.



According to space-engine simulations, the Hill sphere could be several AU! Sounds plausible. It would be able to capture alot of stuff.
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alan
post Sep 2 2016, 08:06 PM
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QUOTE (Mongo @ Aug 31 2016, 08:18 PM) *

Odd gap in the perihelia:
QUOTE
In our survey simulator, we find that 71% of detections should occur in the 50 AU to 75 AU range. Since we found 2 EDTNOs and 1 IOC object, none of which had perihelia in the 50 to 75 AU range, the probability of this occurring by chance is about 2%

Other surveys have found the other 19 known ETNOs, none of which have perihelion in the 50 AU to 75 AU range. If other surveys have similar biases to our own, the probability of this occurring by chance is roughly 0.29^19 = 6×10^−11 or about 7 σ assuming Gaussian statistics
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Mongo
post Sep 3 2016, 02:06 AM
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QUOTE (alan @ Sep 2 2016, 08:06 PM) *
Odd gap in the perihelia:

There were a number of very interesting objects found, that were buried in the paper:

QUOTE
The TNO 2013 FY27 was found to be one of the most distant and one of the brightest outer solar system objects discovered in this survey. The 22 magnitude r-band magnitude and 80.5 AU distance of 2013 FY27 give the object an absolute magnitude of about 2.9. This makes 2013 FY27 one of the top ten intrinsically brightest TNOs and thus it could be a top ten largest TNO as well. Though the diameter and albedo are unknown, assuming an albedo of 0.1 yields a diameter around 1000 km.

QUOTE
The first object that enters into the outer Oort cloud yet has perihelion greater than Neptune was discovered as part of this survey. 2014 FE72 has a semi-major axis around 2155 AU and an aphelion distance of some 4000 AU.
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HSchirmer
post Apr 3 2017, 01:49 PM
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Crowdsourcing astronomy
https://www.zooniverse.org/projects/marckuc...worlds-planet-9

60,000 volunteer astronomers sort through 4 million objects in 3 days,
they've identified 4 candidates for a large planet out in the kuiper belt.

QUOTE
http://www.universetoday.com/134824/four-c...anet-9-located/

A concentrated three-day search for a mysterious, unseen planet in the far reaches of our own solar system has yielded four possible candidates.
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JRehling
post Apr 6 2017, 03:55 AM
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Interesting work. I would note that, if there is no more than one major distant planet, the false positive rate is, as a matter of logical necessity, either 75% or 100%, so interpret this preliminary work in that light. I think I'd title this work more cautiously with that extremely high false positive rate in mind. It's really not evidence of such a planet at all – it's a useful direction for future work.
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TheAnt
post Apr 8 2017, 12:25 PM
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Indeed it's catchy headline, and that attract readers.
If we instead lift a sentence from the main text and use this as a headline:

"We’ve managed to rule out a planet about the size of Neptune being in about 90 per cent of the southern sky..."
The whole matter is turned on it's head.

But yes, interesting effort nevertheless. smile.gif
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Holder of the Tw...
post Jun 23 2017, 02:22 PM
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Now there is evidence of another fairly large body out there, this one around Mars mass and closer than 100 AU.

Warped Kuiper disk

It took a while, but I tracked down the paper on the LPL site:

Draft Version
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Holder of the Tw...
post Jul 13 2017, 02:20 PM
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The latest ...

New evidence in support of the {Trans-Neptunian Gas Giant} hypothesis
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