What mass range object is designated as a 'failed star' that contracts and cools without sustained hydrogen fusion?

Answer

Brown Dwarf ( $\approx 0.013$ to $0.08 M_{\odot}$ )

Objects falling below the threshold of approximately 0.08 solar masses do not possess enough gravity to reach the core temperature required for sustained hydrogen fusion, resulting in them becoming brown dwarfs.

What mass range object is designated as a 'failed star' that contracts and cools without sustained hydrogen fusion?

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