GMAT Sentence Correction (SC) | The stars, some of them at tremendous speeds, are in motion

Dear experts,
Like the planets, the stars are in motion, some of them at tremendous speeds, but they are so far away from the Earth that their apparent positions in the sky do not change enough for their movement to be observed during a single human lifetime

is "some of them at tremendous speeds" an absolute phrase, which modifies the preceding clause.

please confirm


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