As per Five Holy Virgins by Pradip Bhattacharya, Tara in Panchkanya is Vali's wife:
Tara,9 wife of Vali and daughter of
the vanara physician Sushena, is the
next kanya we meet in the Ramayana.
The end note further clarifies it:
9 Not to be confused with Tara, wife of
Brihaspati, preceptor of the gods who
elopes with his disciple Chandra, or with