Simulations suggest Planet Nine may have been a rogue

Planet Nine: A world that shouldn't exist
An artist's conception of Planet Nine. Credit: Caltech/R. Hurt (IPAC)

(—Space researchers James Vesper and Paul Mason with New Mexico State University have given a presentation at this year's American Astronomical Science meeting outlining the results of simulations they have been running to learn more about Planet Nine—a planet that many in the space science community believe exists far beyond Pluto. They presented evidence suggesting that if Planet Nine is out there, it is likely a rogue.

Planet Nine was first predicted to exist just two years ago, when a team of investigators noticed what appeared to be an unknown gravitational influence in the outer . Since then, other researchers have also noticed gravitational influences consistent with a planet on the order of 10 times the size of Earth. Prior research has also suggested that if the planet does exist, it likely orbits the sun at approximately 1000 AU (the Earth resides at 1 AU). In this new effort, the researchers ran 156 computer simulations designed to show what sort of impact such a planet would have on our solar system if it came from somewhere else—a rogue planet that wandered close enough to our sun to be captured by its .

Rogue are those that either developed outside of the solar system, or developed in another star system and then somehow escaped. In either event, they travel alone through space.

The researchers report that their simulations showed that 60 percent of the times a rogue planet encountered our solar system, it came in and then left, sometimes taking another smaller planet with it. In 40 percent of cases, however, the rogue was captured and remained in orbit. The simulations also suggested that if such a rogue was captured, it could orbit the sun at the speculated distance and that it was unlikely that a planet any bigger than Neptune has ever entered our solar system—the orderliness of our system suggests it has not been disturbed since the period when the solar system was created.

Space scientists have expressed a strong belief in recent months that Planet Nine will be confirmed soon, perhaps as early as next year as more effort is put into finding it.

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More information: 424.05 Simulation of Rogue Planet Encounters with the Solar System: Is Planet 9 a Captured Rogue? (James Vesper)

Rogue, or free-floating, planets may be abundant in the Galaxy. Several have been observed in the solar neighborhood. They have been predicted to even outnumber stars by a large fraction, and may partially account for dark matter in the disk of the galaxy, as the result of circumbinary planet formation. We performed N-body simulations of rogue encounters with the solar system with a variety of impact parameters. We find that Jupiter mass and higher rogues leave a significant imprint on planetary system architecture. Rogue formation models are therefore constrained by observed planetary system structure. We speculate that if rogue planets are abundant as predicted, then, Planet 9 may be a captured rogue.

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Citation: Simulations suggest Planet Nine may have been a rogue (2017, January 12) retrieved 20 October 2019 from
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Jan 12, 2017
Fine and dandy but, we have yet to prove that such a planet actually exists.

Jan 12, 2017
I'm still more inclined to believe it was a single close encounter with another star.

Jan 12, 2017
Planet Fourteen (and counting). If it even exists.

Jan 12, 2017
It's Yuggoth! Y'AI'NG'NGAH YOG-SOTHOTH H'EE-L'GEB F'AI THRODOG UAAAH! Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn!

But, seriously... If planet 9 (from outer space, apparently) does actually exist, that 1000AU distance would put it right on the inner edge of the Oort Cloud. Could it be responsible for disturbing the OC & flinging long-period comets towards the inner solar system? Some have previously hypothesized a dwarf companion star (Nemesis) doing this from the other side of the OC, but that's been largely discredited.

Jan 18, 2017
Well, actually we may have found the complwte set of orbital parameters back in 2002. We called it Vulcan then.


Parameter C"EV Orbit C*EV Orbit Max. Error Min Error
Period (years) 4969.0 5058.7 +30.4/- 24.3 +/- 11.5
Orbital Eccentricity 0.537 0.514 +0.088/-0.035 +/- 0.0085
Orbital Inclination 48.44o 48.38o +3.12o/-9.05o +/- 0.23o
Longitude of the Ascending Node 189.0o 188.6o +/- 1.3o +/- 1.3o
Argument Of Perihelion 257.8o 258.06o +6.11o/-13.47o +/- 0.90o
Time of Aphelion (years) 1970 AD 1970 AD +/- 1.0 +/- 1.0

Since then, we have focused on the C"EV orbit and been able to verify four of the six orbital parameters.

Jan 18, 2017
Forbes found three of these orbital parameters in 1880.

Table 2 - Vulcan's Orbital Parameters
Parameter Value Max. Error Min. 2 Sigma Error Forbes'(1880)*
Period (years) 4969.0 +30.4/- 24.3 +/- 11.5 5000
Orbital Eccentricity 0.537 +0.088/-0.035 +/- 0.0085 not cal.
Orbital Inclination 48.44o +3.12o/-9.05o +/- 0.23o 45o
Longitude of the Ascending Node 189.0o +/- 1.3o +/- 1.3o 185o
Argument Of Perihelion 257.8o +6.11o/-13.47o +/- 0.90o not cal.
Time of Aphelion (years) 1970 AD +/- 1.0 +/- 1.0 not cal.
* Proc. Roy. Soc. Edinburgh; Vol. 10, 1878 - 80; pg. 426 - 430

Jan 18, 2017
We have independently calculated Vulcan's period to be 4969.3 years closely matching our 4969.0 years. The U of Az astronomers have found two possible values for Planet Nine's orbital inclination, being 18 or 48 degrees, the latter closely matches our 48.44 +/- 0.23 (two sigma) degrees.

Planet Nine" update: Possible resonances beyond the Kuiper belt?

Our body is safely within Hynek's 50 billion miles or Van Flandern's 490 AU meaning it won't be ejected by a passing star. It's aphelion is about 41.6 billion miles. It's eccentricity suggests that dwarf planets BIDEN and Eris were once planets of this ultra tiny brown dwarf star.


Jan 18, 2017
Fine and dandy but, we have yet to prove that such a planet actually exists.

Patience. At the hard-to-do end of research (which is basically all research) you always first get a hint, then tease apart the strands of evidence until you finally find something (or until you stumble upon a totally different explanation in the process).

The search for planet nine is currently in the 'tease apart the strands' phase.

Jan 28, 2017

The search for planet nine is currently in the 'tease apart the strands' phase.

We already found planet nine. It's called either Pluto or Neptune, depending on whether you hold to the geophysical definition of planet that sets a 2000-kilometer minimum diameter (thereby excluding Ceres from full planethood) or the one that just goes by mass, meaning Ceres is planet five. Then you have Makemake, Haumea, Eris, and this object which may or may not actually exist.

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