MATL, 17 bytes
Yb94ih'(.*)'h6&XX
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How?
Yb - Split the input at spaces, place the results in a cell array
94 - ASCII code for ^ character
ih - Get the input (say "frac"), concatenate '^' and the input
'(.*)'h - Push the string '(.*)' into the stack, concatenate '^frac' and '(.*)'. So now we have '^frac(.*), a regex that matches "frac" at the beginning of the string and captures whatever comes after.
6&XX - Run regexp matching, with 6& specifying 'Tokens' mode i.e., the matched capture groups are returned instead of the entire match.
Implicitly output the results.
