Why is Jupiter often debated as a 'failed star' despite its immense size compared to other planets?

Answer

Its current mass is too low to initiate even deuterium fusion.

Jupiter is far too light to achieve stellar reactions; specifically, it lacks the required mass (estimated to be about 25 times its current mass) needed even for deuterium fusion, the lower tier of stellar activity.

Why is Jupiter often debated as a 'failed star' despite its immense size compared to other planets?
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