What is a planet? The International Astronomical Union (IAU) said that the definition for a planet is now officially known as "a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape and (c) has cleared the neighborhood around its orbit." At the same time, new moons are also being discovered, both around existing planets and within these mysterious new worlds. Once the existence of a moon is confirmed and its orbit determined, the moon is given a final name by the International Astronomical Union (IAU), the organization that assumed this task since 1919.

Planet	Named by the IAU	Provisionally Named
Mercury	0	0
Venus	0	0
Earth	1	0
Mars	2	0
Jupiter	49	14
Saturn	52	8
Uranus	27	0
Neptune	13	0
Total Moons Named: 144
Body Type	Named by the IAU	Provisionally Named
Known Dwarf Planets	3	0
Dwarf Planet Watch List	6	6

References:

• USGS Astrogeology: Gazetteer of Planetary Nomenclature Planetary Body Names and Discoverers
• Solar System Dynamics - Planetary Satellite Discovery Circumstances