Non-isothermal effects on Be disks

TL;DR

This paper introduces an analytical model for Be star disks that accounts for non-isothermal effects, linking disk thermal structure to infrared observations and validated by numerical simulations.

Contribution

It presents a simple two-component analytical model for Be star disks that incorporates non-isothermal effects and connects brightness profiles with thermal structure.

Findings

Non-isothermality significantly impacts infrared fluxes.

The model accurately describes the disk's brightness profile.

Validation against numerical simulations confirms the model's effectiveness.

Abstract

In the last decade, the viscous decretion disk model has emerged as the new paradigm for Be star disks. In this contribution, we propose a simple analytical model to estimate the continuum infrared excess arising from these circumstellar disks, in the light of the currently accepted scenario. We demonstrate that the disk can be satisfactorily described by a two component system: an inner optically thick region, which we call the pseudo-photosphere, and a diffuse outer part. In particular, a direct connexion between the disk brightness profile and the thermal structure is derived, and then confronted to realistic numerical simulations. This result quantifies how the non-isothermality of the disk ultimately affects both infrared measured fluxes and visibilities.