What planetary characteristic plays a critical role in maintaining surface pressure and trapping heat within the HZ?

Answer

The composition and density of a planet's atmosphere

While distance sets baseline temperature, atmospheric composition and density are critical for trapping heat and maintaining the pressure required to keep water in a liquid state.

What planetary characteristic plays a critical role in maintaining surface pressure and trapping heat within the HZ?
astronomyplanetssolar systemhabitable zonegoldilocks zone