Abstract
The thermal evolution of substellar mass objects in which grain formation occurs in the outer envelope or atmosphere is investigated. Models spanning the brown-dwarf mass range are constructed and their cooling histories are investigated. Henyey-code calculations verify that the interior is fully adiabatic for the stages of evolution investigated. At effective temperatures below 2500 K, 'cloud' formation in the atmosphere causes a strong variation in opacity with effective temperature. The effect on the temperature profile is a strong function of particle size and vertical distribution of grains. The interior and the atmosphere are matched at the pressure level corresponding to the top of the deep convection zone; through this matching, the radius and luminosity as a function of time are perturbed by grain formation. The results are used to construct luminosity functions for substellar objects and to compare two candidate brown dwarfs with the models. 29 refs.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have