Pluto before Charon was discovered. Pluto is more than twice the diameter and a dozen times the mass of the dwarf planet Ceres, the largest object in the asteroid belt. It is less massive than the dwarf planet Eris, a trans-Neptunian object discovered in 2005, though Pluto has a larger diameter of 2376.6 km compared to Eris's approximate diameter of 2326 km. Determinations of Pluto's size had been complicated by its atmosphere, and hydrocarbon haze. In March 2014, Lellouch, de Bergh et al. published findings regarding methane mixing ratios in Pluto's atmosphere consistent with a Plutonian diameter greater than 2360 km,
Definition of planet storms [Titan] shouldn't be put into the same category, whatever you call it. However, he goes on to say that, "For most people, considering round satellites (including our Moon) "planets" violates the idea of what a planet is." Alan Stern has argued that location should not matter and that only geophysical attributes should be taken into account in the definition of a planet, and proposes the term "satellite planet" for a planet-sized satellite. In 2017, Stern, K. D. Runyon et al. proposed a new geophysical definition of planet that defined a planet simply as an object large enough to be