"frequent object" is correct and usable in written English.
You can use it to refer to a noun that is often referred to or encountered in a particular context, for example: "The beach ball is a frequent object of play for children at the seaside."
But the most frequent object of my neighbours' ire is the referee or his fellow officials.
He was also the frequent object of protests outside the Indians' home field.
China's human rights community is the frequent object of government surveillance and oppression.
By contrast, expectation-based accounts such as surprisal predict that the less frequent object relative should be harder to process.
Tax policies, social mores and limited investment opportunities made entrepreneurial fortunes exceedingly rare -- and entrepreneurs themselves the frequent object of envy and suspicion.
The absence of spotters in Iraq and Syria, known by their military acronym JTACs, has been a frequent object of criticism for the Pentagon in Congress.
Both the poem and its singsong metre have been frequent objects of parody.
Peace advocates on both sides of the border have become marginal figures, and, in the Palestinian territories, frequent objects of harassment and intimidation by militants.
After the Sept. 11 attacks, Sikh men, conspicuous by their turbans, became frequent objects of misplaced anti-Muslim invective around the country.
Generalized autoregressive conditional hetereoscedastic (GARCH) models and stochastic volatility models are examples of processes that fall under this general theory.NonGaussian linear models and nonlinear time series models have also been frequent objects of study in my research.
Mice, ants, fish and worms have all been sent to the station to see how zero-gravity affects their bodies and behaviour, but probably the most frequent objects of study are the astronauts themselves.
