Understand
I describe DESPOTIC, a code to Derive the Energetics and SPectra of Optically Thick Interstellar Clouds.
- DESPOTIC represents such clouds using a one-zone model, and can calculate line luminosities, line cooling rates, and in restricted cases line profiles using an escape probability formalism.
- It also includes approximate treatments of the dominant heating, cooling, and chemical processes for the cold interstellar medium, including cosmic ray and X-ray heating, grain photoelectric heating, heating of the dust by infrared and ultraviolet radiation, thermal cooling of the dust, collisional energy exchange between dust and gas, and a simple network for carbon chemistry.
- Based on these heating, cooling, and chemical rates, DESPOTIC can calculate clouds' equilibrium gas and dust temperatures, equilibrium carbon chemical state, and time-dependent thermal and chemical evolution.