Answer
The head of the Peripatetic School when Aristarchus was there was Strato of Lampsacus, who succeeded Theophrastus in 287 BC. Strato was known for his emphasis on empirical observation and his skepticism of traditional religious beliefs. He made significant contributions to the fields of physics and physiology and was regarded as one of the most important philosophers of the Peripatetic School after Aristotle and Theophrastus.