x.com/NASAhistory/status/2091888259529932891
1 correction found
Must orbit its host star
The 2006 IAU definition adopted that day did not say a planet must orbit its "host star"; it specifically said a planet must be "in orbit around the Sun."
Full reasoning
The post says these were the criteria adopted at the International Astronomical Union meeting 20 years earlier. But the official resolution passed on August 24, 2006 was narrower than that.
The IAU's own vote-result page states that members agreed a planet is a celestial body that "is in orbit around the Sun" and labels the resolution "Definition of a 'Planet' in the Solar System." NASA's current explainer reproduces the same official text and separately notes that whether the definition applies to exoplanets "remains to be seen."
So the voted-on 2006 definition was not a general "host star" rule for all planetary systems. It was specifically a Solar System definition using the Sun, not any star. Saying the adopted criterion was "Must orbit its host star" therefore misstates the wording and scope of the IAU definition.
2 sources
- IAU 2006 General Assembly: Result of the IAU Resolution votes
The IAU members gathered at the 2006 General Assembly agreed that a "planet" is defined as a celestial body that (a) is in orbit around the Sun ... IAU Resolution: Definition of a "Planet" in the Solar System.
- What is a Planet? | NASA
Here is the text of the IAU's Resolution B5: Definition of a Planet in the Solar System ... A planet is a celestial body that (a) is in orbit around the Sun ... Whether our definitions of planet can be applied to these newly found objects remains to be seen.