Dwarf main sequences stars are not a subset of main sequence stars, nor are dwarf galaxies a subset of galaxies. They are simply smaller stars, smaller galaxies, and smaller planets. Red dwarf (spectral type M) stars should not be confused with degenerate white dwarf stars. While they are both very small stars, one still fuses hydrogen (the red dwarf), whereas the other is a dead star (the white dwarf) and no longer fuses hydrogen.After all, dwarf stars are a subset of stars and dwarf galaxies are a subset of galaxies, shouldn't a dwarf planet be a type of a planet?
Why "should" they? Would that change in structure of the categorization lead to a change in their physical properties? Of course not. The utility of a categorization is to enable generalization (abstraction) and/or improve communication. Which purpose would that change address and how? Your question seems to me to be equivalent to asking whether the word "planet" should be capitalized. What possible difference would it make? Many (if not most) of their similarities with the planets are known, so there seems to be no good reason to invent a more general category which includes both planets and dwarf planets and nothing else. You may want to read more about the criticisms of the IAU definition of planet - Wikipedia article of that name discussed it, iirc.
Why? What difference does it make?If dwarf planets are not planets, they should call them by some other name, not "dwarf planets".
This is a red herring argument. Interestingly, red herrings are almost always neither red nor herrings.If dwarf planets are not planets, they should call them by some other name, not "dwarf planets".
Every science has its oxymoronic terms, including astronomy. For example, neutron star and Martian geology.I don't know of a single other case in all of astronomy where a "X Y" is not a type of Y, except for "dwarf planet."
Not amongst dynamicists. Your hopes are most likely as moot as were those of the discoverers of the first four asteroids, which were categorized as planets for the first half of the 19th century.I think it's quite a silly way to build a category and I hope they come to their senses soon. But it's rather moot, because most actual practitioners of planetary astronomy certainly do consider dwarf planets to be planets, indeed they consider moons to be planets also.
All the same, neither of those are counterexamples to my point.Every science has its oxymoronic terms, including astronomy. For example, neutron star and Martian geology.
So your logic is, if you can cite a subset of astronomers who care about the official meaning of "planet", and I can cite a subset who don't care at all what other people regard as "planets", that makes my point moot? I don't follow that logic. What I'm saying is, there is an entire subfield of astronomy called "planetary astronomy" which, in general, includes essentially zero interest in the IAU classification of "planet", but a whole lot of interest in the common physics, and contrasts, among objects that are of interest to "planetary astronomy." In that latter camp, a "dwarf planet" is very much a subclass of "planet", expressly because of the interesting physics they share with what the IAU might wish to call a "planet." For them, it makes no difference at all how many planets we count in the solar system, it is their physics that they care about.Not amongst dynamicists. Your hopes are most likely as moot as were those of the discoverers of the first four asteroids, which were categorized as planets for the first half of the 19th century.
