I’m somewhat surprised that the disingenuous way in which the IAU came to that particular vote wasn’t addressed but I understand this needed to be an argument FOR Pluto’s status rather than AGAINST an organizations entrenched biases (though there were references to that elitism).

Thank you for this piece.

Step 1: Define the minimum dominant mass (MDM) of a solar system

The mass of the smallest rounded celestial body in orbit around a star (or stellar remnant) that has cleared the neighborhood of [or is dynamically dominant in] its orbit using Jean-Luc Margot’s planetary discriminant (where Π ≥ 1).

For example, for our solar system Mercury is the MDM; in the solar system known as Kepler-37, the MDM is Kepler-37b (which has a diameter slightly greater than Earth’s moon). See the following link for a more technical explanation of Margot’s practical planetary discriminant:

http://mel.ess.ucla.edu/jlm/publications/Margot15.aj.PlanetDefinition.pdf.

Step 2: Define the term planet

A celestial body that…

(1) orbits one or more stars or stellar remnants;
(2) is a gravitationally dominant member of its solar system, defined as follows:
(a) has cleared the neighborhood of [or is dynamically dominant in] its orbit (e.g., Margot’s Π ≥ 1)
OR (Note: Skip 2b if 2a is already fulfilled, for example, to expedite exoplanet classification.)
(b) has a mass >= the MDM of its solar system;
(3) has a mass below 13 Jupiter masses, a nominal value close to the limiting mass for thermonuclear fusion of deuterium.

With this definition, as long as Earth and Jupiter orbit the sun directly, they will always remain planets regardless of their hypothetical location in the solar system (e.g., a “remote” Jupiter that orbits in the Oort Cloud or a “remote” Earth” that orbits at 100 AUs from the the sun). And with this definition, you don’t set an arbitrary cut-off point for planethood for all other solar systems at Mercury but instead use a contextual cut-off point for planethood unique to each solar system (as in the case of Kepler-37).

Everything less than the MDM will be a dwarf planet or small solar system body (SSSB, or sub-planetary mass object) so there won’t be any more Jupiter-like planets potentially mislabeled as “dwarf planets” because of their given location within a solar system. Rogue planets and large rounded satellites will remain separate categories under the classification of planetary mass objects (PMOs).

In summary, planets are by all rights the dominant players of any given solar system (after their parent star(s) of course). Dwarf planets, large rounded satellites, rogue planets, and SSSBs are, for various reasons, not dominant players of solar systems.