A discussion on "officially called a planet"

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SUMMARY

The discussion centers on the classification of a hypothetical Trans-Neptunian Object (TNO) referred to as "planet 9," which, if detected, would not meet the International Astronomical Union's (IAU) current criteria for a planet. The criteria include orbiting the sun, having sufficient mass to be round, not being a satellite of another object, and clearing debris from its orbit. The participants argue that a 10 Earth mass (10 Me) TNO would likely have an eccentric orbit, making it difficult to classify as a planet under the existing definitions. This raises questions about the need for redefining what constitutes a planet.

PREREQUISITES
  • Understanding of the International Astronomical Union (IAU) planet classification criteria
  • Familiarity with Trans-Neptunian Objects (TNOs)
  • Knowledge of orbital mechanics and eccentric orbits
  • Awareness of the historical context of Pluto's reclassification
NEXT STEPS
  • Research the IAU's criteria for planet classification and any proposed changes
  • Explore the characteristics and significance of Trans-Neptunian Objects (TNOs)
  • Study the implications of orbital mechanics on celestial body classification
  • Investigate the historical debate surrounding Pluto's status as a planet
USEFUL FOR

Astronomers, astrophysicists, planetary scientists, and anyone interested in the evolving definitions of celestial bodies and the classification of planets.

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Forking a subject that was in risk of hi-jacking anther thread here.

If the hypothetical TNO "planet 9" is detected , it would not fit the IAU's current criteria of being a planet. What would it be ?

For the sake of discussion let's assume 10 Me and estimated likely distance and orbital period.

Would it fit an existing category or would it require a new term or another redefinition of what a "planet" is?
 
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A really big TNO(Trans-Neptunian Object)?
 
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Current definition:
  • orbits the sun
  • has sufficient mass to be round, or nearly round
  • is not a satellite (moon) of another object
  • has removed debris and small objects from the area around its orbit
https://www.space.com/25986-planet-definition.html

A more specific take on the 4th criteria is that it has a mass greater than the combined mass of all objects in a similar orbit.

Given the distance, I think such objects tend to have eccentric orbits and trouble clearing them. Thus I don't think they can be classified as planets.
 
Yes , the orbit clearing thing is what caught Plluto out, but a 10Me it can't be called a dwarf planet; neither is it a rogue if it is orbiting.

It's planet sized but not a planet. Will we need to move the goalposts again?
 
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