"Dwarf planet" is not a category of planet. It's a category of objects which are NOT planets.
More accurate measurements of Neptune's mass, including measurements taken by Voyager 2, have eliminated either the need or the presence of a supermassive Planet X. It isn't there- at least not within 50 AUs, which is nearly double Pluto's maximum distance from the sun.
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More accurate measurements of Neptune's mass, including measurements taken by Voyager 2, have eliminated either the need or the presence of a supermassive Planet X. It isn't there- at least not within 50 AUs, which is nearly double Pluto's maximum distance from the sun.