A Classifying Milky Way planets by what they´re bound to and originate from

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The discussion focuses on classifying planets in the Milky Way based on their binding and origin. It highlights that current detection methods primarily rely on a planet's interaction with its host star, which limits the identification of certain types of planets. The conversation references the existence of free-floating planets, with estimates suggesting around 70 to over 100 have been detected. Additionally, it clarifies that there are no known planets that are unbound from the Milky Way or expelled from other galaxies currently passing through it. The classification of Milky Way planets remains complex due to the limitations of existing detection techniques.
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TL;DR Summary
Relative numbers of various groups
How many planets now in Milky Way are:
  1. Bound to a particular star or a star system of a few stars?
  2. Not bound to any particular star nor a star system of a few stars but bound to Milky Way and possibly to some star system of many stars?
  3. Not bound to Milky Way, but originating in Milky Way, recently accelerated to unbound and on the way out?
  4. Not bound to Milky Way nor originating here, expelled from another galaxy and currently passing through Milky Way?
 
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Of what we have detected:
1. All of them.
2, 3, 4. None of them.

This is because our detection methods are based on the planet's interaction with its host star.
 
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russ_watters said:
This is because our detection methods are based on the planet's interaction with its host star.
Not true. See https://en.wikipedia.org/wiki/Rogue_planet:
"The two first discovery papers use the names isolated planetary-mass objects (iPMO)[9] and free-floating planets (FFP).[10] Most astronomical papers use one of these terms.[11][12][13] The term rogue planet is more often used for microlensing studies, which also often uses the term FFP.[14][15] A press release intended for the public might use an alternative name. The discovery of at least 70 FFPs in 2021, for example, used the terms rogue planet,[16] starless planet,[17] wandering planet[18] and free-floating planet[19] in different press releases."
 
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