The probable trajectory of the ninth planet in night sky?

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Discussion Overview

The discussion centers around the probable trajectory and position of the hypothesized ninth planet, as suggested by Konstantin Batygin and Michael E. Brown. Participants explore the orbital elements and physical properties of the planet, as well as the uncertainties and missing parameters necessary for accurately determining its trajectory.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that the exact position of the ninth planet is unknown and discusses specific orbital parameters such as mass, inclination, eccentricity, and semi-major and semi-minor axes.
  • Another participant points out that additional parameters are necessary to locate the planet, specifically the longitude of the ascending node and the mean anomaly at a given epoch.
  • Some participants emphasize that the lack of exact orbital parameters is why the planet remains unnamed and unobserved, questioning the implications of a potentially migrating perihelion on the orientation of the orbit.

Areas of Agreement / Disagreement

Participants generally agree on the uncertainty surrounding the orbital parameters of the ninth planet, but multiple competing views remain regarding the implications of these uncertainties and the necessary parameters for plotting its trajectory.

Contextual Notes

Limitations include missing assumptions about the orientation of the orbit and the potential for the perihelion to be migrating, which complicates the determination of the planet's trajectory.

sami_m
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What would be the propable trajectory and position of the ninth planet that has been suggested few days ago (20.1.2016 by Konstantin Batygin and Michael E. Brown) ?

if i understood correctly, the exact position of the planet is unknown and has not been evaluated.

But by looking this article http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22/pdf
the orbital elements and physical properties they used in one of their simulation looks like to be (page 9 second column)

m > 10 m_{earth} mass
i = 30 ° inclination, this would mean that the estimated trajectory is a great circle that is in the 30° angle to the celestial equator. But i don't know what is the direction of the perihelion, aphelion or ascending node?
e = 0.6 eccentricity
a = 700 Au , b = 550 Au semimajor axis and semiminor axis
ω = 150 ° argument of perihelion (from what direction?)

but i don't know how to estimate error limits. Also the discussion section says that the analysis is not yet complete and other possibilities may not be excluded.
 
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There are are a couple of parameters missing from that list if you wanted to locate the planet or plot its trajectory:
The longitude of the ascending node
The mean anomaly at a given epoch. (basically, you have to know at what point of its orbit it is in on some date to know where it will be at some other date.)

Also, the inclination is measured with respect to the ecliptic, not the celestial equator.
 
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If we knew the exact orbital parameters, we wouldn't call it "Planet Nine". It would be observed in a telescope and would have a real name.
 
Vanadium 50 said:
If we knew the exact orbital parameters, we wouldn't call it "Planet Nine". It would be observed in a telescope and would have a real name.

they don't mention there the orientation of the orbit, is it because , if the perihelion is of the orbit is slowly migrating, then the orientation can be anything now?
 

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