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Comment by jessriedel | Hacker News Reader

No. That’s not what wikipedia says, and I feel confident asserting that an Earth-mass object forming on its own would not be considered a brown dwarf by the vast majority of astronomers. (Maybe it would also not be considered a “planet”, due to some Pluto-adjacent technicalities, but then what do people call it? I’m betting they use “rogue planet” in practice.)

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I think you are missing the size distinction and range for rogue planets, which I specifically highlight.

Claims about self formation pertain to rouge planets as a class, which includes brown dwarfs. That does not mean an earth mass object IS a brown dwarf.

If you want to want to focus on Wikipedia text, it also says:

>Pre-JWST observations have shown that objects below 3-5 MJ are unlikely to form on their own.[4] Observations in 2023 in the Trapezium Cluster with JWST have shown that objects as massive as 0.6 MJ might form on their own, not requiring a steep cut-off mass[1]

Those limits are ~1,000 earth masses and ~200 earth masses, respectively

https://en.wikipedia.org/wiki/Rogue_planet#Formation_like_a_...

No, an Earth-mass object forming on its own would not be considered a brown dwarf, but an Earth-mass object is incredibly unlikely to form on its own. An object that small will have almost certainly been formed in an accretion disk and been ejected.

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